Fix help sentence in network log create --enable

As the documentation states [1], the default in network log objects is
to be enabled, not disabled.

[1] https://docs.openstack.org/neutron/latest/admin/config-logging.html

Change-Id: I13e9d1132fc38104e6e85d9c8442bc7506adc2fd

neutronclient/osc/v2/logging/network_log.py

@@ -58,11 +58,11 @@ def _get_common_parser(parser):
     enable_group.add_argument(
         '--enable',
         action='store_true',
-        help=_('Enable this log (default is disabled)'))
+        help=_('Enable this log'))
     enable_group.add_argument(
         '--disable',
         action='store_true',
-        help=_('Disable this log'))
+        help=_('Disable this log (default is enabled)'))
     return parser