MINOR: h1: Reject requests with different occurrences of the header host

There is no reason for a client to send several headers host. It even may be
considered as a bug. However, it is totally invalid to have different values for
those. So now, in such case, an error is triggered during the request
parsing. In addition, when several headers host are found with the same value,
only the first instance is kept and others are skipped.
1 file changed