chore(Build): Remove version from bower.json

Per http://bower.io/docs/creating-packages/#version

Closes #3748

Author: c0bra

lib/grunt/plugins.js

@@ -292,7 +292,6 @@ module.exports = function(grunt) {
 
     var json = {
       "name": "angular-ui-grid",
-      "version": currentTag,
       "main": releaseFiles,
       "ignore": [],
       "dependencies": {