Update hux-blog.less

Author: TwperBody

less/hux-blog.less

@@ -530,7 +530,6 @@ samp {
   background: no-repeat center center;
   background-color: @brand-gray;
   background-attachment: scroll;
-  background-size: 80% auto; /* 新增背景图片大小控制 */
   .background-cover;
   // NOTE: Background images are set within the HTML using inline CSS!
   margin-bottom: 0px; /* 0 on mobile, modify by Hux */