[dovecot] 0.99.9-test5

[Timo Sirainen]

- Fixed startup crashing in POP3 server

- Several fixes to opening index file which needs to be rebuilt. Before
it didn't always rebuild the index but just fallbacked to using only
memory, and that could have been quite slow since all mails in the
mailbox were opened and parsed.

- If there's nothing in mail_cache_fields, index rebuilding doesn't open
the file anymore. This should make in-memory indexes a lot faster than
before, but it could also mean some performance hits later. If client
wants to fetch all mails from the mailbox, the same thing has to be done
anyway.. This needs more thinking actually what is the optimal
behaviour.

- Support /etc/shadow-like file for passdb.