Fix the InstallPackage item
Fix the InstallPackage item

It failed to take qbs.installPrefix and qbs.installSourceBase into
account.

Task-number: QBS-1019
Change-Id: I243cfaaf9f83b818d5ab1210b96a107a4e22380f
Reviewed-by: Jake Petroules <2d627e1cecd5435752fa500bacbe05f7cc90c369@qt.io>

qtproject/qt-labs-qbs,qtproject/qt-labs-qbs,qt-labs/qbs,qt-labs/qbs,qt-labs/qbs,qt-labs/qbs,qt-labs/qbs,qt-labs/qbs,qtproject/qt-labs-qbs,qtproject/qt-labs-qbs,qt-labs/qbs,qtproject/qt-labs-qbs,qtproject/qt-labs-qbs,qtproject/qt-labs-qbs