Found by latest clang scan-build.

Nothing changes in the code logic.

The old code seems to have worked correctly already, but now it's a bit
clearer how it was intended to work.

Fixes "warning: cast to smaller integer type" with new clang.

Default is now debug logging, which is used for the IMAP plugins. The LDA Sieve
plugin uses info logging.

When no insertion point was found, it would always insert the new rule at the
beginning, rather than at the end.

lib-sieve: plugins: vacation: cmd-vacation - Consolidate message address comparison in separate function.

Core is using {old,new}_foo for the RENAME IMAP command event, so let's
follow suit.

Core is using {old,new}_foo for the RENAME IMAP command event, so let's
follow suit.

Before, it created a separate trace file for each individual filtered message.

Before, it created a separate trace file for each individual filtered message.

It is generally a bad idea to add a potentially unlimited string to a filename,
especially when it contains a mailbox name.