Fix qt4 binary path detection
Fix qt4 binary path detection

Commit e8b186610738a16fe8ddaacd39797d863828c7aa removed the use of
QT_INSTALL_BINS property if QT_HOST_BINS doesn't exists to set the
binaryPath. But qt4 needs it because QT_HOST_BINS doesn't exist.

Change-Id: I3e5bc10d3b4839bd62a1202ff5cbc939f0a3b2b0
Reviewed-by: Ivan Komissarov <96f14e4d07227e958f51f7d2898113639e9498d9@gmail.com>
Reviewed-by: Christian Kandeler <3aa99dcdd3f0cac61fb81c2a11771c0cc2497607@qt.io>

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