Remove AuthorizationFailure exception

The AuthorizationFailure exception isn't used anywhere, so
remove it.

Fix bug 1015940.

Change-Id: Ie6da74b63e3d1658c8ae26c272222f00f1209e38

glanceclient/common/exceptions.py

@@ -7,10 +7,6 @@ class CommandError(Exception):
     pass
 
 
-class AuthorizationFailure(Exception):
-    pass
-
-
 class NoTokenLookupException(Exception):
     """This form of authentication does not support looking up
        endpoints from an existing token."""

glanceclient/shell.py

@@ -283,8 +283,6 @@ class OpenStackImagesShell(object):
             args.func(client, args)
         except exc.Unauthorized:
             raise exc.CommandError("Invalid OpenStack Identity credentials.")
-        except exc.AuthorizationFailure:
-            raise exc.CommandError("Unable to authorize user")
 
     @utils.arg('command', metavar='<subcommand>', nargs='?',
                help='Display help for <subcommand>')