use RHTSupport in RHEL workflows

references RHBZ#917778

Signed-off-by: Michal Toman <mtoman@redhat.com>
Signed-off-by: Jakub Filak <jfilak@redhat.com>
SPEC: only pull RHTSupport by default on RHEL6

jfilak:
* libreport-anaconda:
+ RHTSupport in RHEL
- Bugzilla in RHEL

references RHBZ#917778

Signed-off-by: Michal Toman <mtoman@redhat.com>
Signed-off-by: Jakub Filak <jfilak@redhat.com>