Fix option to not cleanup containers not in config

In https://review.opendev.org/#/c/707278/ we added an option to
not cleanup containers not in config, but it's broken. We should
use --no-cleanup with action='strore_false' and default=True.

Change-Id: I9570b5e4e68b8e1d4181bd5c514193d648a9128f

paunch/cmd.py

@@ -80,9 +80,9 @@ class Apply(command.Command):
             help=('Whether or not we disable the containers healthchecks')
         )
         parser.add_argument(
-            '--cleanup',
+            '--no-cleanup',
             dest='cleanup',
-            action='store_true',
+            action='store_false',
             default=True,
             help=('Whether or not we delete containers missing in the config')
         )