Use the subcomand parsed args instead of the base

Pass the subcomand's arguments instead of the base ones to the endpoint
creation call when quering the `/versions` endpoint. Passing the wrong
arguments will end in the auth_requirement not being identified and an
error 'Expected Endpoint' will be raised as no endpoint will be gotten
from keystone.

This patch also removes an unnecessary mock in the test code related to
this fix.

Depends-On Iefeb9bc123f8c65fecd0cba585ecd3eb349b23a6
Change-Id: I46088130b9175798e3719e43f48dc474fbc8a251
Closes-bug: #1504058

glanceclient/shell.py

@@ -654,7 +654,7 @@ class OpenStackImagesShell(object):
 
         if not options.os_image_api_version and api_version == 2:
             switch_version = True
-            client = self._get_versioned_client('2', options)
+            client = self._get_versioned_client('2', args)
 
             resp, body = client.http_client.get('/versions')