[Dovecot] 1.0.rc21 released

http://dovecot.org/releases/dovecot-1.0.rc21.tar.gz http://dovecot.org/releases/dovecot-1.0.rc21.tar.gz.sig

Just one fix. Maybe the one big thing in Dovecot v2.0.* will be a test suite, which is run before any release. :)

- Cache file handling could have crashed rc20