remove pbr as runtime dependency

Use importlib.metadata to return the same version info instead of
depending on pbr at runtime.

Change-Id: Idce5e238ae45cf07394d1264bccf89e9a6e8f28e
Signed-off-by: Doug Goldstein <cardoe@cardoe.com>

Author: cardoe

openstackclient/__init__.py

@@ -11,12 +11,8 @@
 #   under the License.
 #
 
-import pbr.version
+import importlib.metadata
 
 __all__ = ['__version__']
 
-version_info = pbr.version.VersionInfo('python-openstackclient')
-try:
-    __version__ = version_info.version_string()
-except AttributeError:
-    __version__ = None
+__version__ = importlib.metadata.version('python-openstackclient')

requirements.txt

@@ -2,8 +2,6 @@
 # date but we do not test them so no guarantee of having them all correct. If
 # you find any incorrect lower bounds, let us know or propose a fix.
 
-pbr!=2.1.0,>=2.0.0 # Apache-2.0
-
 cryptography>=2.7 # BSD/Apache-2.0
 cliff>=4.13.0 # Apache-2.0
 iso8601>=0.1.11 # MIT