Fix "in" comparisons with one element tuples

A single value enclosed in parentheses is not a tuple (it needs a comma
after the element) therefore the comparisons like 'if foo in ("bar")'
are wrong.

Closes-Bug: #1248443
Change-Id: I29a2227c9d83efc17ecfacc86d507d75edd4eaca

nova/tests/compute/test_virtapi.py

@@ -91,7 +91,7 @@ class FakeVirtAPITest(VirtAPIBaseTest):
         else:
             e_args = args
 
-        if method in ('block_device_mapping_get_all_by_instance'):
+        if method == 'block_device_mapping_get_all_by_instance':
             e_kwargs = {}
         else:
             e_kwargs = kwargs

nova/virt/libvirt/driver.py

@@ -2594,7 +2594,7 @@ class LibvirtDriver(driver.ComputeDriver):
         # In managed mode, the configured device will be automatically
         # detached from the host OS drivers when the guest is started,
         # and then re-attached when the guest shuts down.
-        if CONF.libvirt.virt_type not in ('xen'):
+        if CONF.libvirt.virt_type != 'xen':
             # we do manual detach only for xen
             return
         try:
@@ -2946,7 +2946,7 @@ class LibvirtDriver(driver.ComputeDriver):
         dev.domain, dev.bus, dev.slot, dev.function = dbsf
 
         # only kvm support managed mode
-        if CONF.libvirt.virt_type in ('xen'):
+        if CONF.libvirt.virt_type in ('xen',):
             dev.managed = 'no'
         if CONF.libvirt.virt_type in ('kvm', 'qemu'):
             dev.managed = 'yes'

nova/virt/xenapi/fake.py

@@ -539,7 +539,7 @@ class SessionBase(object):
         _db_content['SR'][sr_ref]['uuid'] = sr_uuid
         _db_content['SR'][sr_ref]['forgotten'] = 0
         vdi_per_lun = False
-        if type in ('iscsi'):
+        if type == 'iscsi':
             # Just to be clear
             vdi_per_lun = True
         if vdi_per_lun: