Record message-id's for rejected emails

In the event that the system is set to do-nothing for POP fetched
emails, and eventually, one of the emails is rejected, ensure that the
message-id is logged so that the message will not be re-fetched, even if it
is undeleted.
Merge pull request #744 from greezybacon/issue/fetch-rejected-loop

Record message-id's for rejected emails

Reviewed-By: Peter Rotich <peter@osticket.com>