[Dovecot] Automatic fd limit changing

I just realized that Dovecot should probably be doing something different with how it handles fd limits. The way it currently works is:

1. It checks some settings and warns at startup if fd limit is lower than what master process might need.

2. For login processes it calculates how many fds are needed and then either increases or decreases it.

So it's automatically and silently increasing fd limit for some processes, but not for others. Should it just automatically increase the limits to all processes when necessary, or never increase and just warn that the limit is too low?