Partial fix for null multi bulk response.

index.js

@@ -784,6 +784,7 @@ Multi.prototype.exec = function (callback) {
 
         var i, il, j, jl, reply, args, obj, key, val;
 
+        if (replies) {
             for (i = 1, il = self.queue.length; i < il; i += 1) {
                 reply = replies[i - 1];
                 args = self.queue[i];
@@ -803,6 +804,7 @@ Multi.prototype.exec = function (callback) {
                     args[args.length - 1](null, reply);
                 }
             }
+        }
 
         if (callback) {
             callback(null, replies);

test.js

@@ -204,6 +204,18 @@ tests.MULTI_6 = function () {
         });
 };
 
+tests.WATCH_MULTI = function () {
+  var name = 'WATCH_MULTI';
+
+  client.watch(name);
+  var multi = client.multi();
+  multi.incr(name);
+  client.incr(name);
+  multi.exec(function (err, replies) {
+    next(name);
+  });
+};
+
 tests.HSET = function () {
     var key = "test hash",
         field1 = new Buffer("0123456789"),