Don't remove output handler if flush_pending is still set after callback.
Don't remove output handler if flush_pending is still set after callback.

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