Mail: optimized discarding invalid SMTP commands. There is no need to scan buffer from s->buffer->pos, as we already scanned the buffer till "p" and wasn't able to find an LF. There is no real need for this change in SMTP, since it is at most a microoptimization of a non-common code path. Similar code in IMAP, however, will have to start scanning from "p" to be correct, since there can be newlines in IMAP literals.