selftest: re-enable nss_winbind via nss_wrapper in the test-envs.

selftest: re-enable nss_winbind via nss_wrapper in the test-envs.

Without exporting these new variables, we can never access or test nss_winbind
from the selftest environments.

This shows that our posixacl test probably needs fixing since now
two subtests fail against plugin_s4_dc:local. This env was just
not complete without winbind in nsswitch. The test failure is
probably due to the strangeness of the AD/DC setup that the
domain administrator uses the same uid as the root user, which
in the selftest case is overridden to be the calling user.

Guenther

Signed-off-by: Günther Deschner <gd@samba.org>
Pair-Programmed-With: Michael Adam <obnox@samba.org>
Reviewed-by: Andreas Schneider <asn@samba.org>
Autobuild-User(master): Günther Deschner <gd@samba.org>
Autobuild-Date(master): Fri Feb 13 20:57:12 CET 2015 on sn-devel-104