start abrt-handle-event in non-interactive mode

libreport reporters have recently started asking for missing
configuration.

This patch tries to avoid hanging on unavailable user input.

Related to rhbz#1018297

Signed-off-by: Jakub Filak <jfilak@redhat.com>
Merge pull request #734 from abrt/rhbz1018297

Adapt abrt-server to the recent changes in Client API