50.samba eventscript should stop/start services when they become (un)managed.

50.samba eventscript should stop/start services when they become (un)managed.

When the value of $CTDB_MANAGES_SAMBA or $CTDB_MANAGES_WINBIND (or
corresponding changes are made to $CTDB_MANAGED_VERSIONS), the
associated service should be started or stopped as necessary.

This add calls to ctdb_start_stop_service() to manage
starting/stopping samba and winbind.

An associated cleanup is made to the initial checks that one of
$CTDB_MANAGES_SAMBA or $CTDB_MANAGES_WINBIND is set, replacing them
with calls to is_ctdb_managed_service().

To handle the winbind cases ctdb_start_stop_service() and
is_ctdb_managed_service() are updated to take an optional service name
parameter.

Signed-off-by: Martin Schwenke <martin@meltin.net>