Fixes #10147: Remove outline from carousel controls on focus

dist/css/bootstrap.css

@@ -6363,6 +6363,7 @@ button.close {
 .carousel-control:focus {
   color: #ffffff;
   text-decoration: none;
+  outline: none;
   opacity: 0.9;
   filter: alpha(opacity=90);
 }

less/carousel.less

@@ -91,6 +91,7 @@
   // Hover/focus state
   &:hover,
   &:focus {
+    outline: none;
     color: @carousel-control-color;
     text-decoration: none;
     .opacity(.9);