ctdb-locking: Add argc parameter to lock_helper_args()

ctdb-locking: Add argc parameter to lock_helper_args()

To make this sane, also add an argv parameter and change the return
type to bool.  Anticipating a subsequent change, make the type of argv
match what is needed by vfork_with_logging() and cast it when passing
to execv().  This also means changing the type of the name member of
struct db_namelist.

Signed-off-by: Martin Schwenke <martin@meltin.net>
Reviewed-by: Amitay Isaacs <amitay@gmail.com>