winbind: provide passwd struct for group sid with ID_TYPE_BOTH mapping (again)

winbind: provide passwd struct for group sid with ID_TYPE_BOTH mapping (again)

https://git.samba.org/?p=samba.git;a=commitdiff;h=394622ef8c916cf361f8596dba4664dc8d6bfc9e
originally introduced the above feature.

This functionality was undone as part of "winbind: Restructure get_pwsid"
https://git.samba.org/?p=samba.git;a=commitdiff;h=bce19a6efe11980933531f0349c8f5212419366a
I think that this semantic change was accidential.

This patch undoes the semantic change and re-establishes the
functionality.

BUG: https://bugzilla.samba.org/show_bug.cgi?id=14141

Signed-off-by: Michael Adam <obnox@samba.org>
Reviewed-by: Christof Schmitt <cs@samba.org>
Reviewed-by: Stefan Metzmacher <metze@samba.org>
Autobuild-User(master): Christof Schmitt <cs@samba.org>
Autobuild-Date(master): Fri Sep 27 17:25:29 UTC 2019 on sn-devel-184