Fix bug when skipping webkit on windows

Do not add "-skip qtwebkit" as one single item to the array, since that
will effectively run configure like this:
.\configure.exe "-skip qtwebkit"

This gave the error:
Unknown option -skip qtwebkit

This was found to be a problem with Windows Powershell, not sure if this
is a problem under command.com

Change-Id: Id2a2e8d4705fc46905450e6a7ac503d6c27710aa
Reviewed-by: Andras Becsi <andras.becsi@digia.com>