dsync: Minor (probably unnecessary) fix for i_stream_read() API usage. Avoid the first read returning -2.
dsync: Minor (probably unnecessary) fix for i_stream_read() API usage.
Avoid the first read returning -2.

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