Improve issue box UI

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

Former-commit-id: 741db760

app/assets/stylesheets/generic/issue_box.scss

@@ -11,7 +11,7 @@
   color: #666;
   margin:20px 0;
   background: #FAFAFA;
-  border: 1px solid #DDD;
+  border: 1px solid #EEE;
   .control-group {
     margin-bottom: 0;
@@ -26,8 +26,6 @@
   }
   .context {
-    border: none;
-    background-color: #f5f5f5;
     border: none;
     border-top: 1px solid #eee;
   }