pack.c: no nil.taint

* pack.c (pack_pack): nil is not taintable.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@47511 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

pack.c

@@ -870,12 +870,12 @@ pack_pack(VALUE ary, VALUE fmt)
 		}
 		else {
 		    t = StringValuePtr(from);
+		    rb_obj_taint(from);
 		}
 		if (!associates) {
 		    associates = rb_ary_new();
 		}
 		rb_ary_push(associates, from);
-		rb_obj_taint(from);
 		rb_str_buf_cat(res, (char*)&t, sizeof(char*));
 	    }
 	    break;