improved the error messages in abrt-server - closes #679

Signed-off-by: Jiri Moskovcak <jmoskovc@redhat.com>
Signed-off-by: Jakub Filak <jfilak@redhat.com>
testsuite: added test for python wrapper for notify_new_path() - related #677

Signed-off-by: Jiri Moskovcak <jmoskovc@redhat.com>