mount: adjust dependencies for remote filesystems

mount: adjust dependencies for remote filesystems

Currently remote mounts automatically get:
 After=remote-fs-pre.target network.target

remote-fs-pre.target is already After=network.target. Just make sure
remote-fs-pre.target is pulled in by remote-fs.target if any remote
filesystems are configured.
For the mount units it is then sufficient to get:
 After=remote-fs-pre.target

Later NetworkManager will hook its NM-wait-online.service into
remote-fs-pre.target.wants in order to remove the need for the administrator
to enable the service manually when he has any remote filesystems.

https://bugzilla.redhat.com/show_bug.cgi?id=787314