add checkbox/radio border for ios in responsive

docs/assets/css/bootstrap-responsive.css

@@ -7,6 +7,9 @@
     display: block;
     line-height: 18px;
   }
+  input[type="checkbox"], input[type="radio"] {
+    border: 1px solid #ccc;
+  }
   .form-horizontal .control-group > label {
     float: none;
     width: auto;

docs/assets/css/bootstrap.css

@@ -533,8 +533,7 @@ input[type="image"], input[type="checkbox"], input[type="radio"] {
   /* IE7 */
 
   line-height: normal;
-  border: none;
-  border: initial;
+  border: 0;
   cursor: pointer;
   border-radius: 0 \0/;
 }