修复lifestyle有货币页面，code review by LZF

@@ -50,7 +50,8 @@ module.exports = function(specificGender) {
     $curNav = $navList.children('.focus');
 
     if (lifestyleType) {
-        navHammer = new Hammer($navList[0]);
+        navHammer = $navList[0] ? new Hammer($navList[0]) : undefined;
+        if (navHammer) {
             navHammer.on('tap', function(e) {
                 var $this = $(e.target).closest('li'),
                     $goods = $('.goods-list'),
@@ -76,6 +77,7 @@ module.exports = function(specificGender) {
                 e.srcEvent.stopPropagation();
             });
         }
+    }
 
     loading.init($('.maybe-like'));