core: support ldaps that returns no supported extended operations

such as samba-4.

Bug-Url: https://bugzilla.redhat.com/show_bug.cgi?id=1172173
Change-Id: I3844cc5cad4ac024afca5dfc1ec2976915e4e717
Signed-off-by: Alon Bar-Lev <alonbl@redhat.com>