imapc: Use SHA1 of message header for guid-forced instead of the entire body.
imapc: Use SHA1 of message header for guid-forced instead of the entire body.

LTD-Beget/dovecot,LTD-Beget/dovecot,LTD-Beget/dovecot,LTD-Beget/dovecot,LTD-Beget/dovecot