Fix help messages

Update help message for openstack security group rule delete
Update help message for openstack security group rule list

Change-Id: I017ffd424ca25b6c62193b91068eb1ba7de6c919
Closes-Bug: #1417854

Author: Ramaraja

openstackclient/compute/v2/security_group.py

@@ -322,7 +322,7 @@ def get_parser(self, prog_name):
         parser.add_argument(
             'group',
             metavar='<group>',
-            help='Create rule in this security group',
+            help='Security group rule to delete (name or ID)',
         )
         parser.add_argument(
             "--proto",
@@ -375,7 +375,7 @@ def get_parser(self, prog_name):
         parser.add_argument(
             'group',
             metavar='<group>',
-            help='Create rule in this security group',
+            help='List all rules in this security group',
         )
         return parser