BUG/MINOR: h1: Don't support LF only at the end of chunks

BUG/MINOR: h1: Don't support LF only at the end of chunks

When the message is chunked, all chunks must ends with a CRLF. However, on
old versions, to support bad client or server implementations, the LF only
was also accepted. Nowadays, it seems useless and can even be considered as
an issue. Just forbid LF only at the end of chunks, it seems reasonnable.

This patch must be backported to 2.9 and probably to all stable versions
because there is no reason to still support LF without CR in this case.