title: PrimeNG: p-autoComplete not clearing value
body: <p>I am using PrimeNG. I wrote code for auto-complete as follows</p>
  
  <pre><code>&lt;p-autoComplete name="searchSuggestions" [(ngModel)]="suggestion" 
  (completeMethod)="searchSuggestions($event)" [suggestions]="searchSuggestionsResult" field="field"&gt;&lt;/p-autoComplete&gt;
  </code></pre>
  
  <p>I am clearing <code>suggestion</code> in a method, but not clearing autocomplete input value. It's clearing only if I select from suggestions.</p>
  
  <pre><code>this.suggestion = undefined;
  </code></pre>