CLEANUP: proto_http: few corrections for gcc warnings.

first, we modify the signatures of http_msg_forward_body and
http_msg_forward_chunked_body as they are declared as inline
below. Secondly, just verify the returns of the chunk initialization
which holds the Authorization Method (althought it is unlikely to fail  ...).
Both from gcc warnings.
diff --git a/src/proto_http.c b/src/proto_http.c
index 74cd260..0c37736 100644
--- a/src/proto_http.c
+++ b/src/proto_http.c
@@ -275,8 +275,8 @@
 
 static int http_apply_redirect_rule(struct redirect_rule *rule, struct stream *s, struct http_txn *txn);
 
-static int http_msg_forward_body(struct stream *s, struct http_msg *msg);
-static int http_msg_forward_chunked_body(struct stream *s, struct http_msg *msg);
+static inline int http_msg_forward_body(struct stream *s, struct http_msg *msg);
+static inline int http_msg_forward_chunked_body(struct stream *s, struct http_msg *msg);
 
 /* This function returns a reason associated with the HTTP status.
  * This function never fails, a message is always returned.
@@ -1589,7 +1589,9 @@
 	if (!p || len <= 0)
 		return 0;
 
-	chunk_initlen(&auth_method, h, 0, len);
+	if (chunk_initlen(&auth_method, h, 0, len) != 1)
+		return 0;
+
 	chunk_initlen(&txn->auth.method_data, p + 1, 0, ctx.vlen - len - 1);
 
 	if (!strncasecmp("Basic", auth_method.str, auth_method.len)) {