Make QtXmlPatterns compile with the QExplicitlySharedDataPointer's static_cast

This module requires the static_casts to happen.

Change-Id: Iea2f5aa8c6033edffd920a6de73509f3ae19721d
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
Reviewed-by: Kevin Funk <kevin.funk@kdab.com>