buffer_insert() and buffer_insert_zero() didn't work correctly when it used to append data.
buffer_insert() and buffer_insert_zero() didn't work correctly when it used
to append data.

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