Msvc2013_xp label for Windows 8.1 x86 added.

Change-Id: Ic2b3bbb92fcabd19938c01ecdd940f15ed2946d2
Reviewed-by: Kai Koehne <kai.koehne@theqtcompany.com>
Reviewed-by: Iikka Eklund <iikka.eklund@theqtcompany.com>