Fix compatibility issues with gerrit 2.5.4

Gerrit 2.5.4 adds:
- a parents Patchet field that was not expected. It is left unused.
- a username Owner field that was not expected. It is added to matches
  and used for shortName.
Signed-off-by: Antoni S. Puimedon <asegurap@redhat.com>
Cap the summary to make max 40 characters
Introduce an execute_search function