Replace QVariant::typeToName usage by QMetaType::typeName call.

Replace QVariant::typeToName usage by QMetaType::typeName call.

Type information is kept in QMetaType class. QVariant is delegating
operations, so it is better to use QMetaType directly.

Change-Id: I91209fa1c9dc4303d6bd47c96824d3cd64ce5291
Reviewed-by: Stephen Kelly <stephen.kelly@kdab.com>
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>