Consider --os-token when using v2

The `_cache_schemas` call currently forces authentication even when the
`auth_token` and `os_image_url` are passed. Instead of handling forced
authentications, let the client use the passed arguments and
authenticate only once if needed.

This was not caught by the existing tests because the call to
`_cache_schemas` was mocked.

Change-Id: I93cec9a68cafc0992d14dab38114d03e25f1e5da
Closes-bug: #1490462

glanceclient/shell.py

@@ -442,12 +442,13 @@ class OpenStackImagesShell(object):
         ks_session.auth = auth
         return ks_session
 
-    def _get_endpoint_and_token(self, args, force_auth=False):
+    def _get_endpoint_and_token(self, args):
         image_url = self._get_image_url(args)
         auth_token = args.os_auth_token
 
-        auth_reqd = force_auth or (utils.is_authentication_required(args.func)
-                                   and not (auth_token and image_url))
+        auth_reqd = (not (auth_token and image_url) or
+                     (hasattr(args, 'func') and
+                      utils.is_authentication_required(args.func)))
 
         if not auth_reqd:
             endpoint = image_url
@@ -537,9 +538,8 @@ class OpenStackImagesShell(object):
 
         return endpoint, token
 
-    def _get_versioned_client(self, api_version, args, force_auth=False):
-        endpoint, token = self._get_endpoint_and_token(args,
-                                                       force_auth=force_auth)
+    def _get_versioned_client(self, api_version, args):
+        endpoint, token = self._get_endpoint_and_token(args)
 
         kwargs = {
             'token': token,
@@ -621,8 +621,7 @@ class OpenStackImagesShell(object):
 
         if not options.os_image_api_version and api_version == 2:
             switch_version = True
-            client = self._get_versioned_client('2', options,
-                                                force_auth=True)
+            client = self._get_versioned_client('2', options)
 
             resp, body = client.http_client.get('/versions')
 
@@ -690,8 +689,7 @@ class OpenStackImagesShell(object):
         if profile:
             osprofiler_profiler.init(options.profile)
 
-        client = self._get_versioned_client(api_version, args,
-                                            force_auth=False)
+        client = self._get_versioned_client(api_version, args)
 
         try:
             args.func(client, args)