Fix for leaking fds with non-writable .customflags files.
Fix for leaking fds with non-writable .customflags files.

damoxc/dovecot,Distrotech/dovecot,Distrotech/dovecot,damoxc/dovecot,Distrotech/dovecot,LTD-Beget/dovecot,LTD-Beget/dovecot,damoxc/dovecot,Distrotech/dovecot,damoxc/dovecot,LTD-Beget/dovecot,Distrotech/dovecot,LTD-Beget/dovecot,LTD-Beget/dovecot,damoxc/dovecot