fix rpcapi version.

In commit ce4dbbd7, the BASE_RPC_API_VERSION was changed to '2.1' in
nova.compute.rpcapi.  This should remain '2.0' until the API goes to
3.X.  Only specify version '2.1' for the method that requires it
(rebuild_instance).

Add a NOTE above each instance of BASE_RPC_API_VERSION to try to help
clarify this for the future.

Change-Id: I06cef44c905e8966505d5fb5b1046d6a0c75d533

nova/cert/rpcapi.py

@@ -33,6 +33,14 @@ class CertAPI(nova.openstack.common.rpc.proxy.RpcProxy):
         1.0 - Initial version.
     '''
 
+    #
+    # NOTE(russellb): This is the default minimum version that the server
+    # (manager) side must implement unless otherwise specified using a version
+    # argument to self.call()/cast()/etc. here.  It should be left as X.0 where
+    # X is the current major API version (1.0, 2.0, ...).  For more information
+    # about rpc API versioning, see the docs in
+    # openstack/common/rpc/dispatcher.py.
+    #
     BASE_RPC_API_VERSION = '1.0'
 
     def __init__(self):

nova/compute/rpcapi.py

@@ -127,10 +127,18 @@ class ComputeAPI(nova.openstack.common.rpc.proxy.RpcProxy):
         1.44 - Adds reserve_block_device_name()
 
         2.0 - Remove 1.x backwards compat
-        2.1 - Adds orig_sys_metadata to rebuild()
+        2.1 - Adds orig_sys_metadata to rebuild_instance()
     '''
 
-    BASE_RPC_API_VERSION = '2.1'
+    #
+    # NOTE(russellb): This is the default minimum version that the server
+    # (manager) side must implement unless otherwise specified using a version
+    # argument to self.call()/cast()/etc. here.  It should be left as X.0 where
+    # X is the current major API version (1.0, 2.0, ...).  For more information
+    # about rpc API versioning, see the docs in
+    # openstack/common/rpc/dispatcher.py.
+    #
+    BASE_RPC_API_VERSION = '2.0'
 
     def __init__(self):
         super(ComputeAPI, self).__init__(
@@ -340,7 +348,8 @@ class ComputeAPI(nova.openstack.common.rpc.proxy.RpcProxy):
                 injected_files=injected_files, image_ref=image_ref,
                 orig_image_ref=orig_image_ref,
                 orig_sys_metadata=orig_sys_metadata),
-                topic=_compute_topic(self.topic, ctxt, None, instance))
+                topic=_compute_topic(self.topic, ctxt, None, instance),
+                version='2.1')
 
     def refresh_provider_fw_rules(self, ctxt, host):
         self.cast(ctxt, self.make_msg('refresh_provider_fw_rules'),
@@ -503,6 +512,14 @@ class SecurityGroupAPI(nova.openstack.common.rpc.proxy.RpcProxy):
         2.0 - Remove 1.x backwards compat
     '''
 
+    #
+    # NOTE(russellb): This is the default minimum version that the server
+    # (manager) side must implement unless otherwise specified using a version
+    # argument to self.call()/cast()/etc. here.  It should be left as X.0 where
+    # X is the current major API version (1.0, 2.0, ...).  For more information
+    # about rpc API versioning, see the docs in
+    # openstack/common/rpc/dispatcher.py.
+    #
     BASE_RPC_API_VERSION = '2.0'
 
     def __init__(self):

nova/console/rpcapi.py

@@ -33,6 +33,14 @@ class ConsoleAPI(nova.openstack.common.rpc.proxy.RpcProxy):
         1.0 - Initial version.
     '''
 
+    #
+    # NOTE(russellb): This is the default minimum version that the server
+    # (manager) side must implement unless otherwise specified using a version
+    # argument to self.call()/cast()/etc. here.  It should be left as X.0 where
+    # X is the current major API version (1.0, 2.0, ...).  For more information
+    # about rpc API versioning, see the docs in
+    # openstack/common/rpc/dispatcher.py.
+    #
     BASE_RPC_API_VERSION = '1.0'
 
     def __init__(self, topic=None):

nova/consoleauth/rpcapi.py

@@ -33,6 +33,14 @@ class ConsoleAuthAPI(nova.openstack.common.rpc.proxy.RpcProxy):
         1.0 - Initial version.
     '''
 
+    #
+    # NOTE(russellb): This is the default minimum version that the server
+    # (manager) side must implement unless otherwise specified using a version
+    # argument to self.call()/cast()/etc. here.  It should be left as X.0 where
+    # X is the current major API version (1.0, 2.0, ...).  For more information
+    # about rpc API versioning, see the docs in
+    # openstack/common/rpc/dispatcher.py.
+    #
     BASE_RPC_API_VERSION = '1.0'
 
     def __init__(self):

nova/scheduler/rpcapi.py

@@ -46,6 +46,14 @@ class SchedulerAPI(nova.openstack.common.rpc.proxy.RpcProxy):
         2.0 - Remove 1.x backwards compat
     '''
 
+    #
+    # NOTE(russellb): This is the default minimum version that the server
+    # (manager) side must implement unless otherwise specified using a version
+    # argument to self.call()/cast()/etc. here.  It should be left as X.0 where
+    # X is the current major API version (1.0, 2.0, ...).  For more information
+    # about rpc API versioning, see the docs in
+    # openstack/common/rpc/dispatcher.py.
+    #
     BASE_RPC_API_VERSION = '2.0'
 
     def __init__(self):

nova/tests/compute/test_rpcapi.py

@@ -227,7 +227,7 @@ class ComputeRpcAPITestCase(test.TestCase):
                 instance=self.fake_instance, new_pass='pass',
                 injected_files='files', image_ref='ref',
                 orig_image_ref='orig_ref',
-                orig_sys_metadata='orig_sys_metadata')
+                orig_sys_metadata='orig_sys_metadata', version='2.1')
 
     def test_reserve_block_device_name(self):
         self._test_compute_api('reserve_block_device_name', 'call',