Exit with EXIT_SUCCESS/EXIT_FAILURE instead of 0 and 1

Fixed for consistency purposes.

rmdir.c

@@ -1,4 +1,5 @@
 #include <stdio.h>
+#include <stdlib.h>
 #include <string.h>
 #include <unistd.h>
 #include <errno.h>
@@ -23,6 +24,6 @@ main(int argc, char **argv)
 					argv[-1], strerror(errno));
 	}
 
-	return 0;
+	return EXIT_SUCCESS;
 }