notify plugin: Don't crash if user-plugin didn't set mailbox_rename. Patch by Ewald Dieterich.
notify plugin: Don't crash if user-plugin didn't set mailbox_rename.
Patch by Ewald Dieterich.

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