quota: Mark the mailbox deleted before starting to reduce quota. This fixes race conditions with another process modifying the same mailbox at the same time.
quota: Mark the mailbox deleted before starting to reduce quota.
This fixes race conditions with another process modifying the same mailbox
at the same time.

damoxc/dovecot,damoxc/dovecot,damoxc/dovecot,damoxc/dovecot,damoxc/dovecot