MINOR: h1-htx: Update h1_copy_msg_data() to ease the traces in the mux-h1

This function now uses the address of the pointer to the htx message where the
copy must be performed. This way, when a zero-copy is performed, there is no
need to refresh the caller's htx message. It is a bit easier to do that way,
especially to add traces in the mux-h1.
4 files changed