Adapted stable branches checks and python

- Showing contact address when login error occurs
- Adapted to new login procedures from bugzilla updates

Bug-Url hook:
- Skiping bugs out of the ovirt-related products
- If the patch is in the stable branch:
 * -1 if no bug-url
 * -1 if any target release incorrect
 * -1 if any private bug

set_POST hook:
- Warning message when not oVirt product
- Warning message when incorrect TR for the branch

set_MODIFIED hook:
- Warning message when not oVirt product

Flow changes:
* Only one review per commit, done by the dispatcher
* Hooks must output the result on stdout and the results will be
  aggregated
* Added more python libraries
* New hook that updates the external tracker metadata
* Changed the directory layout

Change-Id: I233f50c77fc2d419a5bc29b2ee5b3299c4bd6293
Signed-off-by: David Caro <dcaroest@redhat.com>