Remove troveclient from the direct dependency list

We don't even actually use troveclient in shade other than the
constructor. Make it an optional import.

Change-Id: I60b924eb8dfb48c53da0befb39cf84e6c1ea8863

extras/install-tips.sh

@@ -21,7 +21,6 @@ for lib in \
         python-keystoneclient \
         python-cinderclient \
         python-neutronclient \
-        python-troveclient \
         python-ironicclient \
         python-heatclient \
         python-designateclient \

releasenotes/notes/no-more-troveclient-0a4739c21432ac63.yaml

@@ -0,0 +1,6 @@
+---
+upgrade:
+  - troveclient is no longer a hard dependency. Users
+    who were using shade to construct a troveclient
+    Client object should use os_client_config.make_legacy_client
+    instead.

requirements.txt

@@ -15,7 +15,6 @@ python-novaclient>=2.21.0,!=2.27.0,!=2.32.0
 python-keystoneclient>=0.11.0
 python-cinderclient>=1.3.1
 python-neutronclient>=2.3.10
-python-troveclient>=1.2.0
 python-ironicclient>=0.10.0
 python-heatclient>=1.0.0
 python-designateclient>=2.1.0

shade/openstackcloud.py

@@ -42,7 +42,6 @@ import magnumclient.client
 import neutronclient.neutron.client
 import novaclient.client
 import novaclient.exceptions as nova_exceptions
-import troveclient.client
 import designateclient.client
 
 from shade.exc import *  # noqa
@@ -1187,6 +1186,11 @@ class OpenStackCloud(_normalize.Normalizer):
 
     @property
     def trove_client(self):
+        warnings.warn(
+            'Using shade to get a trove_client object is deprecated. If you'
+            ' need a raw troveclient.client.Client object, please use'
+            ' make_legacy_client in os-client-config instead')
+        import troveclient.client
         if self._trove_client is None:
             self._trove_client = self._get_client(
                 'database', troveclient.client.Client)