Remove some cruft from forums SASS

lms/static/sass/_discussion.scss

@@ -824,11 +824,6 @@ body.discussion {
       border: 1px solid transparent;
       text-align: center;
 
-      .current-board {
-        white-space: normal;
-
-      }
-
       span {
         font-size: 14px;
         font-weight: 700;
@@ -836,12 +831,7 @@ body.discussion {
         color: #333;
         text-shadow: 0 1px 0 rgba(255, 255, 255, .8);
       }
-      .drop-arrow {
-        font-size: 16px;
-      }
-      .drop-arrow {
-        font-size: 16px;
-      }
+
       .drop-arrow {
         font-size: 16px;
       }