selftest: re-enable nsswrapper integration testing for dc and member environments.

selftest: re-enable nsswrapper integration testing for dc and member environments.

There are some failures:

- The dc environment fails consistently due to duplicate uid,
  (for the calling user and the domain administrator).
  ==> Marked as knownfail.

- The s3member environment only fails under very strange
  circumstances:
  - one needs to run the unix.whoami test in the
    member and s3member environment for the local.nss
    test to fail in the s3member:local env. The failure
    is then related to builtin administrators sharing
    a gid with a different group.
    --> This is really really strange!!!
    ==> Marked as knownfail.

Pair-Programmed-With: Guenther Deschner <gd@samba.org>

Signed-off-by: Michael Adam <obnox@samba.org>
Signed-off-by: Günther Deschner <gd@samba.org>
Autobuild-User(master): Günther Deschner <gd@samba.org>
Autobuild-Date(master): Mon Mar  2 19:50:55 CET 2015 on sn-devel-104