Merge branch 'missed-boards-css' into 'master'

Removes duplicated CSS for EE

See merge request gitlab-org/gitlab-ee!10486

app/assets/stylesheets/pages/boards.scss

@@ -663,45 +663,6 @@
   }
 }
 
-.board-milestone-list {
-  > li {
-    padding-left: 0;
-    padding-right: 0;
-  }
-
-  a {
-    padding-left: 25px;
-  }
-
-  .fa-check {
-    margin-left: -18px;
-  }
-}
-
-.board-inner-milestone-dropdown {
-  margin-top: 10px;
-
-  .dropdown-menu {
-    position: fixed;
-    left: 10px;
-    top: 175px;
-    min-width: 200px;
-  }
-}
-
-.board-config-modal {
-  width: 440px;
-
-  .block {
-    padding: $gl-padding 0;
-
-    // add a border between all items, but not at the start or end
-    + .block {
-      border-top: solid 1px $border-color;
-    }
-  }
-}
-
 .board-card-info {
   color: $gl-text-color-secondary;
   white-space: nowrap;