Remove the use of a template qUnused function for ICC

ICC 12 does not seem to need this.

Change-Id: I98e9d530e767c4d24424f0c2b5d763f863e85fe4
Reviewed-by: Stephen Kelly <stephen.kelly@kdab.com>
Reviewed-by: Bradley T. Hughes <bradley.hughes@nokia.com>
(backported from qt5/qtbase d3951a5b0f4fe9731d1512668b43f51bd98bd84e)
Reviewed-by: Jędrzej Nowacki <jedrzej.nowacki@theqtcompany.com>
Only add the res_file to the generated files if there is no rc_file

If both the rc_file and res_file was added to the project then in MSVC
2012 it would cause an error complaining of a duplicated resource.

Task-number: QTBUG-29826
Change-Id: Ib3401b423208cd8c90895038c9cbadd80c39b542
Reviewed-by: Joerg Bornemann <joerg.bornemann@digia.com>
(cherry picked from qtbase/fa1fb5ed945650d45cf9b61906232cfbae11360e)
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@theqtcompany.com>