Require int value for --limit option

Currently the value passed to the --limit option is not validated as
part of argument parser and results in an ugly error.

$ openstack stack list --limit a
invalid literal for int() with base 10: 'a'
$

This enables the validation in argument parser to require integer,
which shows more clear error.

$ openstack stack list --limit a
openstack stack list: error: argument --limit: invalid int value: 'a'
$

Change-Id: I17397bc202a08de63b715fa15d0f33754393c226

heatclient/osc/v1/software_config.py

@@ -80,6 +80,7 @@ class ListConfig(command.Lister):
         parser.add_argument(
             '--limit',
             metavar='<limit>',
+            type=int,
             help=_('Limit the number of configs returned')
         )
         parser.add_argument(

heatclient/osc/v1/stack.py

@@ -537,6 +537,7 @@ class ListStack(command.Lister):
         parser.add_argument(
             '--limit',
             metavar='<limit>',
+            type=int,
             help=_('The number of stacks returned')
         )
         parser.add_argument(

heatclient/tests/unit/osc/v1/test_software_config.py

@@ -83,7 +83,7 @@ class TestListConfig(TestConfig):
         arglist = ['--limit', '3']
         parsed_args = self.check_parser(self.cmd, arglist, [])
         self.cmd.take_action(parsed_args)
-        self.mock_client.software_configs.list.assert_called_with(limit='3')
+        self.mock_client.software_configs.list.assert_called_with(limit=3)
 
     def test_config_list_marker(self):
         arglist = ['--marker', 'id123']