Help Search: Fix re-index button

The re-index button was connected to the wrong help search engine.

Change-Id: I945853886a8cb0462eef71d22c48a1ac92c1eec1
Reviewed-by: Eike Ziller <eike.ziller@theqtcompany.com>
Fix MSVC2010 compilation

Broken in cabf14ba3003e57cce2917f8fad50a09d3967f43

Change-Id: I83da1254ceb4636f2b75f5ef75c9f790fd13f140
Reviewed-by: Nikolai Kosjar <nikolai.kosjar@theqtcompany.com>