TieredMenu with appendTo=body isn't removed

[brunopalaoro]

I'm submitting a ...

[ x ] bug report

**Plunkr Case (Bug Reports)**
http://plnkr.co/wGmzrIDMWUujaBMHECbs

**Current behavior**
If a TieredMenu has the propertu attachTo=body, it never gets removed from the dom, because the ngOnDestroy only removes if there's a documentClickListener, and in various case it doen't have.

**Expected behavior**
Remove the menu from the page when it get's destroyed.

**Minimal reproduction of the problem with instructions**
If you have a menu and you go to another route, for instance.
In the plunker I made a call to ngOnDestroy and after it a document.querySelector('.ui-tiered-menu') to show that the menu still in there.

**Please tell us about your environment:**
* **Angular version:** 4.3.6

* **PrimeNG version:** 4.2.0

* **Browser:** [Tested on Chrome and Firefox]

[cagataycivici]

Obrigado!