Merge pull request #16279 from twbs/fix-16276

Make .btn in .btn-toolbar float:left too

less/button-groups.less

@@ -36,6 +36,7 @@
   margin-left: -5px; // Offset the first child's margin
   &:extend(.clearfix all);
 
+  .btn,
   .btn-group,
   .input-group {
     float: left;