Added appropriate error message for designate cli

This patch adds appropriate error message for Exception
generated when running cli without authentication and
endpoint.

Change-Id: I78fe2f8db9a2cfa716c0071a7da404817dd5fbdd
Closes-Bug: #1490843

designateclient/cli/base.py

@@ -52,7 +52,10 @@ class Command(CliffCommand):
 
             self.error_output(parsed_args, columns, values)
         except ks_exceptions.EndpointNotFound as e:
-            self.app.log.error("No endpoint was found: %s", e.message)
+            self.app.log.error('No endpoint was found. You must provide a'
+                               'username or user id via --os-username, '
+                               '--os-user-id, env[OS_USERNAME] or '
+                               'env[OS_USER_ID]')
 
             return 1