fs: dlm: return positive pid value for F_GETLK

commit 92655fbd upstream.

The GETLK pid values have all been negated since commit 9d5b86ac
("fs/locks: Remove fl_nspid and use fs-specific l_pid for remote locks").
Revert this for local pids, and leave in place negative pids for remote
owners.

Cc: stable@vger.kernel.org
Fixes: 9d5b86ac ("fs/locks: Remove fl_nspid and use fs-specific l_pid for remote locks")
Signed-off-by: Alexander Aring <aahringo@redhat.com>
Signed-off-by: David Teigland <teigland@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>