qbs build: Re-add rpaths for our autotests
qbs build: Re-add rpaths for our autotests

They got accidentally removed in 5a1bb1db8e.

Change-Id: I75a78507eddd9c225d846870d9515807c6117f27
Reviewed-by: Jake Petroules <2d627e1cecd5435752fa500bacbe05f7cc90c369@qt.io>

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