fetch: don't bail if fetching an mbox fails

Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
query: add a 'release' keyword for searching for specific releases

Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
scan: add a Message-ID field to all patches

This will allow better commit detection and also provides useful
information for the commit log.

Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>