Use 'KeyValueAppendAction' from osc-lib

Does what it says on the tin. This action was added to osc-lib in change
If73cab759fa09bddf1ff519923c5972c3b2052b1.

Change-Id: I51efaa096bb26e297d99634c5d9cca34c0919074
Signed-off-by: Stephen Finucane <sfinucan@redhat.com>

openstackclient/compute/v2/server.py

@@ -201,36 +201,6 @@ def _prep_server_detail(compute_client, image_client, server, refresh=True):
     return info
 
 
-# TODO(stephenfin): Migrate this to osc-lib
-class KeyValueAppendAction(argparse.Action):
-    """A custom action to parse arguments as key=value pairs
-
-    Ensures that ``dest`` is a dict and values are lists of strings.
-    """
-
-    def __call__(self, parser, namespace, values, option_string=None):
-        # Make sure we have an empty dict rather than None
-        if getattr(namespace, self.dest, None) is None:
-            setattr(namespace, self.dest, {})
-
-        # Add value if an assignment else remove it
-        if '=' in values:
-            key, value = values.split('=', 1)
-            # NOTE(qtang): Prevent null key setting in property
-            if '' == key:
-                msg = _("Property key must be specified: %s")
-                raise argparse.ArgumentTypeError(msg % str(values))
-
-            dest = getattr(namespace, self.dest)
-            if key in dest:
-                dest[key].append(value)
-            else:
-                dest[key] = [value]
-        else:
-            msg = _("Expected 'key=value' type, but got: %s")
-            raise argparse.ArgumentTypeError(msg % str(values))
-
-
 class AddFixedIP(command.Command):
     _description = _("Add fixed IP address to server")
 
@@ -719,7 +689,7 @@ class CreateServer(command.ShowOne):
         parser.add_argument(
             '--hint',
             metavar='<key=value>',
-            action=KeyValueAppendAction,
+            action=parseractions.KeyValueAppendAction,
             default={},
             help=_('Hints for the scheduler (optional extension)'),
         )