make sure i_buffer_read() sets buf_errno to 0 at eof.
make sure i_buffer_read() sets buf_errno to 0 at eof.

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