Fix placeholder with Bootstrap theme

Author: tkrotoff

src/bootstrap/match.tpl.html

@@ -3,7 +3,7 @@
    ng-class="{'text-success': $select.selected == undefined}"
    ng-disabled="$select.disabled"
    ng-click="$select.activate()">
-  <span ng-hide="$select.selected" class="text-muted">{{placeholder}}</span>
+  <span ng-hide="$select.selected" class="text-muted">{{$select.placeholder}}</span>
   <span ng-show="$select.selected" ng-transclude></span>
   <span class="caret"></span>
 </a>