[Users] Customize path for impacache

[Redfox1000 at gmx.de]

Hei Paul,

> That's unusual and can only be the case if you have an MH mailbox.
> Choose the location on the Advanced page of your IMAP account, use
> the Browse button and select an IMAP folder.

maybe I am lost. What kind of folder am I supposed to choose if not one
of a MH mailbox? If I choose an IMAP folder, mails are again stored in
/.claws-mail/imapcache ... Since it is not(?) possible to change this
for the "source" folder I don't know how to do it for the target
folder.

Matthias