remove font-sizes from button group btn sizes

less/button-groups.less

@@ -37,17 +37,6 @@
   margin-left: 1px;
 }
 
-// Reset fonts for other sizes
-.btn-group > .btn-mini {
-  font-size: @font-size-mini;
-}
-.btn-group > .btn-small {
-  font-size: @font-size-small;
-}
-.btn-group > .btn-large {
-  font-size: @font-size-large;
-}
-
 // Set corners individual because sometimes a single button can be in a .btn-group and we need :first-child and :last-child to both match
 .btn-group > .btn:first-child {
   margin-left: 0;