Check for MDL-related componentHandler not being present

- Same as in document library, preparing for tests

ng2-components/ng2-alfresco-search/src/components/alfresco-search-control.component.ts

@@ -82,8 +82,10 @@ export class AlfrescoSearchControlComponent implements AfterViewInit {
     }
 
     ngAfterViewInit() {
+        if (componentHandler) {
             componentHandler.upgradeAllRegistered();
         }
+    }
 
     getTextFieldClassName(): string {
         return 'mdl-textfield mdl-js-textfield' + (this.expandable ? ' mdl-textfield--expandable' : '');