lockd: Show pid of lockd for remote locks

Commit 9d5b86ac ("fs/locks: Remove fl_nspid and use fs-specific l_pid
for remote locks") specified that the l_pid returned for F_GETLK on a local
file that has a remote lock should be the pid of the lock manager process.
That commit, while updating other filesystems, failed to update lockd, such
that locks created by lockd had their fl_pid set to that of the remote
process holding the lock.  Fix that here to be the pid of lockd.

Also, fix the client case so that the returned lock pid is negative, which
indicates a remote lock on a remote file.

Fixes: 9d5b86ac

 ("fs/locks: Remove fl_nspid and use fs-specific...")
Cc: stable@vger.kernel.org

Signed-off-by: Benjamin Coddington <bcodding@redhat.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>