Support fallback to classic compositor

So that I don't need to keep changing this or worry about bad commits,
support falling back to the classic compositor if the new compositor
doesn't work.

userspace/init.c

@@ -84,10 +84,17 @@ void start_compositor() {
 	int pid = fork();
 	if (!pid) {
 		char * tokens[] = {
+			"/bin/compositor2",
+			NULL
+		};
+		execvp(tokens[0], tokens);
+
+		char * _tokens[] = {
 			"/bin/compositor",
 			NULL
 		};
-		int i = execvp(tokens[0], tokens);
+		execvp(_tokens[0], _tokens);
+
 		exit(0);
 	} else {
 		syscall_wait(pid);