Remove cinder credentials command

This function has been broken for some time, this patch replaces it with
a helpful message.  This function can be removed in the next release.

Change-Id: Ic0a4177e7818c0a1493c15d9e496dc14c63ae7a3
Close-Bug: #1615695

cinderclient/v2/shell.py

@@ -966,13 +966,9 @@ def do_endpoints(cs, args):
 
 def do_credentials(cs, args):
     """Shows user credentials returned from auth."""
-    catalog = cs.client.service_catalog.catalog
-
-    # formatters defines field to be converted from unicode to string
-    utils.print_dict(catalog['user'], "User Credentials",
-                     formatters=['domain', 'roles'])
-    utils.print_dict(catalog['token'], "Token",
-                     formatters=['audit_ids', 'tenant'])
+    warnings.warn(
+        "``cinder credentials`` is deprecated, use ``openstack token issue`` "
+        "indead.")
 
 
 @utils.arg('tenant',

releasenotes/notes/remove-credentials-e92b68e3bda80057.yaml

@@ -0,0 +1,5 @@
+---
+other:
+  - The cinder credentials command has not worked for several releases. The
+    preferred alternative is to us the openstack token issue command, therefore
+    the cinder credentials command has been removed.