Add daemon to check users and groups uidNumber/gidNumber

Users created on non-zentyal domain controllers won't have these attributes
set.
Add precondition for uid/gid number check daemon
remove unnecessary su and bash usage
Merge branch 'master' into scabrero/samba-adc-uid-gid-daemon

Conflicts:
	main/samba/ChangeLog
Merge pull request #1592 from Zentyal/scabrero/samba-adc-uid-gid-daemon

Scabrero/samba adc uid gid daemon