jobqueue: Use explicit retry when refreshLinks can't get a lock

jobqueue: Use explicit retry when refreshLinks can't get a lock

While RefreshLinksJob is de-duplicated by page-id, it is possible
for two jobs to run for the same page ID if the second one was queued
after the first one started running. In that case they the newer
one must not be skipped or ignored because it will have newer
information to record to the database, but it also has no way
to stop the old one, and we can't run them concurrently.

Instead of letting the lock exception mark the job as error,
making it implicitly retry, do this more explicitly, which avoids
logspam.

Bug: T170596
Co-Authored-By: Aaron Schulz <aschulz@wikimedia.org>
Change-Id: Id2852d73d00daf83f72cf5ff778c638083f5fc73