Docs: Add the remote tag to the badge image
Docs: Add the remote tag to the badge image

Latest docutils complains about images that are not in the same repo
unless they are properly marked as `:remote:`.

Change-Id: Ic305813473eabbe1ab43a78fc767e0d80b097a07

vedujoshi/tempest,masayukig/tempest,openstack/tempest,cisco-openstack/tempest,masayukig/tempest,openstack/tempest,cisco-openstack/tempest,Juniper/tempest,vedujoshi/tempest,Juniper/tempest