修正bootstrap-select下拉箭头重影问题

static/bootstrap-select/js/bootstrap-select.js

@@ -525,7 +525,6 @@
           '<button type="button" class="' + this.options.styleBase + ' dropdown-toggle" data-toggle="dropdown"' + autofocus + ' role="button">' +
           '<span class="filter-option pull-left"></span>&nbsp;' +
           '<span class="bs-caret">' +
-          this.options.template.caret +
           '</span>' +
           '</button>' +
           '<div class="dropdown-menu open" role="combobox">' +