imapc: Don't assert-crash when trying to sync a mailbox with MAILBOX_FLAG_SAVEONLY. We can just skip the sync, because we don't do anything except save mails.
imapc: Don't assert-crash when trying to sync a mailbox with MAILBOX_FLAG_SAVEONLY.
We can just skip the sync, because we don't do anything except save mails.

dscho/dovecot,dscho/dovecot,dscho/dovecot,dscho/dovecot,dscho/dovecot