Improving the help of the lock command.

The lock command allows you to block the actions
on the server for the non-admin users. Improving
the help so that api users understands better
what locking a server implies.

Change-Id: I925c946751602dc0f6bd1d31b514bc20bca585fa
Closes-Bug: #1366279

Author: pnavarro

doc/source/command-objects/server.rst

@@ -225,7 +225,7 @@ List servers
 server lock
 -----------
 
-Lock server
+Lock a server. A non-admin user will not be able to execute actions
 
 .. program:: server lock
 .. code:: bash

openstackclient/compute/v2/server.py

@@ -659,7 +659,8 @@ def take_action(self, parsed_args):
 
 
 class LockServer(command.Command):
-    """Lock server"""
+
+    """Lock a server. A non-admin user will not be able to execute actions"""
 
     log = logging.getLogger(__name__ + '.LockServer')