And more fixes.
* Dovecot now fails to load plugins that were compiled for different
Dovecot version, unless version_ignore=yes is set. This needs to be
explicitly set in plugins, so out-of-tree plugins won't have this
check by default.
- pop3_lock_session=yes could cause deadlocks, and with maildir the
uidlist lock could have been overridden after 2 minutes causing
- PAM wasted CPU by calling a timeout function 1000x too often
- Trash plugin was more or less broken with multiple namespaces and
with multiple trash mailboxes