sambaundoguididx: Add flags=ldb.FLG_DONT_CREATE_DB and port to Python3

sambaundoguididx: Add flags=ldb.FLG_DONT_CREATE_DB and port to Python3

In py3 we need to add an extra str() around the returned ldb value to
enable .split() to be used.

BUG: https://bugzilla.samba.org/show_bug.cgi?id=13978

Signed-off-by: Andrew Bartlett <abartlet@samba.org>
Reviewed By: Noel Power <npower@samba.org>

Autobuild-User(master): Noel Power <npower@samba.org>
Autobuild-Date(master): Thu May 23 14:25:52 UTC 2019 on sn-devel-184

(cherry picked from commit 1a9da378a1505daff498be6d6355debd73526a1a)