Fix up multipath docker indentation

Fix up multipath docker indentation

Deploying a multipathd container gives the following error:
failed: [localhost] (item={'key': u'config_files', 'value': [{u'dest': u'/', u'merge': True, u'source':
u'/var/lib/kolla/config_files/src-iscsid/*', u'preserve_properties': True}]}) =>
{\"checksum\": \"72ad81489381571c5043b7613f6828b06ae364bd\", \"failed\": true, \"item\":
{\"key\": \"config_files\", \"value\": [{\"dest\": \"/\", \"merge\": true, \"preserve_properties\": true,
\"source\": \"/var/lib/kolla/config_files/src-iscsid/*\"}]}, \"msg\": \"Destination directory does not exist\"}

The reason is the wrong indentation of the config_files key in the
multipath docker service.

Change-Id: I0e1fbb9eb188a903994b9e5da90ab4a6fb81f00a
Closes-Bug: #1708129