Support separately defined Samba resources

Don't manipulate the ctdb_manages_winbind parameter during join;
(bnc#892982).
- 3.1.11

Signed-off-by: David Disseldorp <ddiss@suse.de>
Merge pull request #29 from ddiss/bnc892982_clustered_join_sets_ctdb_manages_winbind

Support separately defined Samba resources