MEDIUM: proxy: make timeout parser a bit stricter

Twice in a week I found people were surprized by a "conditional timeout" not
being respected, because they add "if <cond>" after a timeout, and since
they don't see any error nor read the doc, the expect it to work. Let's
make the timeout parser reject extra arguments to avoid these situations.

src/proxy.c

@@ -233,6 +233,11 @@ static int proxy_parse_timeout(char **args, int section, struct proxy *proxy,
 		}
 	}
 
+	if (*args[2] != 0) {
+		memprintf(err, "'timeout %s' : unexpected extra argument '%s' after value '%s'.", name, args[2], args[1]);
+		retval = -1;
+	}
+
 	*tv = MS_TO_TICKS(timeout);
 	return retval;
 }