Only build QML examples if the QtQuick module is available

Task-number: QTBUG-31255

Change-Id: If0b46400416c82858bca509903ef711b9fb250ea
Reviewed-by: Jocelyn Turcotte <jocelyn.turcotte@digia.com>
Merge remote-tracking branch 'origin/release' into stable

Change-Id: Iaef8f563467bbcdffb41991e1a0e3cfa85297969
Merge remote-tracking branch 'origin/stable' into dev

Change-Id: Ib0b25e1a510be39aa911b8b452a9b0067e630659