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.
diff --git a/src/proto_http.c b/src/proto_http.c
index 78c1ac3..4a6e6d3 100644
--- a/src/proto_http.c
+++ b/src/proto_http.c
@@ -6851,7 +6851,7 @@
 	b_adv(chn->buf, ret);
 	msg->next -= ret;
 	if (msg->next)
-		goto missing_data_or_waiting;
+		goto waiting;
 
 	FLT_STRM_DATA_CB(s, chn, flt_http_end(s, msg),
 			 /* default_ret */ 1,
@@ -6867,11 +6867,12 @@
 			       /* on_error    */ goto error);
 	b_adv(chn->buf, ret);
 	msg->next -= ret;
+
+  waiting:
 	if (!(chn->flags & CF_WROTE_DATA) || msg->sov > 0)
 		msg->sov -= ret;
 	if (!HAS_DATA_FILTERS(s, chn))
 		msg->chunk_len -= channel_forward(chn, msg->chunk_len);
-  waiting:
 	return 0;
   error:
 	return -1;
@@ -6965,7 +6966,7 @@
 	b_adv(chn->buf, ret);
 	msg->next -= ret;
 	if (msg->next)
-		goto missing_data_or_waiting;
+		goto waiting;
 
 	FLT_STRM_DATA_CB(s, chn, flt_http_end(s, msg),
 		    /* default_ret */ 1,
@@ -6981,11 +6982,12 @@
 			  /* on_error    */ goto error);
 	b_adv(chn->buf, ret);
 	msg->next -= ret;
+
+  waiting:
 	if (!(chn->flags & CF_WROTE_DATA) || msg->sov > 0)
 		msg->sov -= ret;
 	if (!HAS_DATA_FILTERS(s, chn))
 		msg->chunk_len -= channel_forward(chn, msg->chunk_len);
-  waiting:
 	return 0;
 
   chunk_parsing_error: