Update vendor-prefix-align.js

Fix for a check if node exists in `_getValName`.
It got broken in cd5306.

Author: tonyganch

lib/options/vendor-prefix-align.js

@@ -84,7 +84,7 @@ module.exports = {
      */
     _getValName: function(node) {
         // TODO: Check that `node[3]` is the node we need
-        if (node[0] !== 'declaration' || !node[3] || !node[3])
+        if (node[0] !== 'declaration' || !node[3] || !node[3][2])
             return;
         if (node[3][2][0] === 'ident')
             return node[3][2][1];