BUG/MINOR: filters: Fix HTTP parsing when a filter loops on data forwarding

BUG/MINOR: filters: Fix HTTP parsing when a filter loops on data forwarding

A filter can choose to loop on data forwarding. When this loop occurs in
HTTP_MSG_ENDING state, http_foward_data callbacks are called twice because of a
goto on the wrong label.

A filter can also choose to loop at the end of a HTTP message, in http_end
callback. Here the goto is good but the label is not at the right place. We must
be sure to upate msg->sov value.