libads: ensure the right ccache is used during spnego bind
When doing spnego sasl bind:
1. Try working without kinit only if a password is not
provided
2. When using kinit, ensure the KRB5CCNAME env var is set
to a private memory ccache, so that the bind is on behalf
of the requested user.
BUG: https://bugzilla.samba.org/show_bug.cgi?id=12007
Signed-off-by: Stefan Metzmacher <metze@samba.org>
Reviewed-by: Uri Simchoni <uri@samba.org>
Autobuild-User(master): Stefan Metzmacher <metze@samba.org>
Autobuild-Date(master): Tue Jul 12 03:23:33 CEST 2016 on sn-devel-144