test-mouse: Fix mouse fd cleanup

I was creating a local variable shadowing the global one. This prevented
cleanup to close it. (this is not really necessary as the program dies
anyway)

userspace/tests/test-mouse/main.cpp

@@ -103,7 +103,7 @@ int main(int argc, char** argv)
 		return 1;
 	}
 
-	int mouse_fd = open(mouse_path, O_RDONLY);
+	mouse_fd = open(mouse_path, O_RDONLY);
 	if (mouse_fd == -1)
 	{
 		fprintf(stderr, "open: ");