[Dovecot] those assertions

Timo,

Just FYI while you're working on the mbox code, I discovered a bug that occasionally causes dovecot to insert a single blank line at the beginning of the mbox, I'm not sure when/how/why.

A single blank line seems to really confuse dovecot, and causes the server to crash when somebody connects to an afflicted mbox. ("Error indexing mbox" in the log, and disconects the user right away).

I fixed it with lots of ugly code at our site (basically just remember that we skipped an intial blank line when doing other operations, instead of skipping it then forgetting later). I suspect there's a more elegant way to do it.

• Mike