remove call to deleted method

Looks while refactoring the limit option to maxTags the isEnabled / enable / disable handling was deleted. (https://github.com/TimSchlechter/bootstrap-tagsinput/commit/ff6c563a387e78e6d4b7f49d8baafbcd8773e2ec). However, there still was one call which now throws an error when calling "removeAll". Removed.