Allocate proper size in in _.restParam.

Since we're putting `rest` at `start` index, `array.length; // => {start + 1}`

lodash.src.js

@@ -7969,7 +7969,7 @@
           case 1: return func.call(this, args[0], rest);
           case 2: return func.call(this, args[0], args[1], rest);
         }
-        var otherArgs = Array(start);
+        var otherArgs = Array(start + 1);
         index = -1;
         while (++index < start) {
           otherArgs[index] = args[index];