Correct C dremove() implementation (not used for implementation of the Lisp DREMOVE function)

The C translation didn't observe that the value of (COND (C X)) is NIL if not C.

	modified:   src/storage.c

src/storage.c

@@ -252,7 +252,8 @@ LispPTR dremove(LispPTR x, LispPTR l) {
       rplaca(l, car(cdr(l)));
       rplacd(l, cdr(cdr(l)));
       return (dremove(x, l));
-    }
+    } else 
+        return (NIL);
   } else {
     z = l;
   lp: