Migrate to pbr.

openstack.common.setup and openstack.common.version are now in the
standalone library pbr, so all projects using those two should
migrate.

Fixes bug 1179007.

Change-Id: I7ac1c37f0bf148619dffff8f454db05fc192e471

.gitignore

@@ -11,8 +11,8 @@ cover
 *~
 build
 dist
-python_novaclient.egg-info
 AUTHORS
 ChangeLog
 novaclient/versioninfo
-setuptools_git-*.egg/
+*.egg
+*egg-info

novaclient/__init__.py

@@ -12,12 +12,7 @@
 #   License for the specific language governing permissions and limitations
 #   under the License.
 
-from novaclient.openstack.common import version
+import pbr.version
 
-version_info = version.VersionInfo('python-novaclient')
-# We have a circular import problem when we first run python setup.py sdist
-# It's harmless, so deflect it.
-try:
-    __version__ = version_info.version_string()
-except AttributeError:
-    __version__ = None
+
+__version__ = pbr.version.VersionInfo('python-novaclient').version_string()