Provide the policy rpm in Bugzilla bug reports

This patch adds the policy rpm string to the user comments of an already
reported bug.

Every comment will contain the following string:

    Version-Release number of selected component:
    selinux-policy-X.XX.X-XXX.YYY.noarch

Red Hat Bugzilla: #1075452
Requires: libreport >= 2.2.2
libreport commit c336fd29a62c3c772957925910a9a2e8e257f88f

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