Nuke shit I added in 4d7b2ddb that shouldn't come until v4

dist/css/bootstrap.css

@@ -1723,7 +1723,6 @@ output {
 .form-control::-webkit-input-placeholder {
   color: #999;
 }
-.form-control:disabled,
 .form-control[disabled],
 .form-control[readonly],
 fieldset[disabled] .form-control {

less/forms.less

@@ -137,10 +137,6 @@ output {
   // HTML5 says that controls under a fieldset > legend:first-child won't be
   // disabled if the fieldset is disabled. Due to implementation difficulty, we
   // don't honor that edge case; we style them as disabled anyway.
-  //
-  // Also note that we include `[disabled]` for IE8. All other browsers take the
-  // `:disabled` selector.
-  &:disabled,
   &[disabled],
   &[readonly],
   fieldset[disabled] & {