涩图模块：修复随机色图不被统计的问题

src/main/java/com/yutou/qqbot/models/setu/GetSeTu.java

@@ -92,6 +92,9 @@ public class GetSeTu extends Model {
                 builder.append(new At(qq))
                         .append(":\n");
                 for (String tag : list) {
+                    if(StringUtils.isEmpty(tag)){
+                        tag="随机";
+                    }
                     builder.append(tag).append("\n");
                 }
                 builder.append("------------------\n");