reporter-bugzilla: support new format keyword %reporter

Readd lost information essential for bug fixing.

Example of line added to a bug report:
reporter:    libreport-2.1.3.36.g5816.dirty

Related to #155

Signed-off-by: Jakub Filak <jfilak@redhat.com>
Signed-off-by: Martin Milata <mmilata@redhat.com>
reporter-bugzilla: remove recently added aux. files from bz reports

last_occurrence - holds a time stamp of last problem occurrence
ureports_counter - holds a number of sent ureports

Closes #155

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