Stabilize qservicemanager_ipc.

Add constructor initializing variables, use QFINDTESTDATA
for service binary and verify its existence. Add QVERIFY
for the interfaces.

Task-number: QTBUG-32666
Change-Id: I83036d9d9c5e7efa0fde6d8d5025b9d8ff1cc8a7
Reviewed-by: Alex <alexander.blasche@digia.com>