Make make_description() output less confusing

Implement ideas of Martin Milata:

I'd remove the empty line before the "Bugzilla:" line, it might not be
immediately clear to which problem the line belongs if there's several
problems in the list.

Also, what about something like:

  Reported:       https://bugzilla.redhat.com/1234
                  https://retrace.fedoraproject.org/report/6789

http://post-office.corp.redhat.com/archives/abrt-devel-list/2013-December/msg00171.html

Related to rhbz#1036585

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