Merge pull request #44 from xhaakon/update

Discard object's all cached properties on ObjectInfoChanged.
Update cleanDirs() in MTPResponder test
[deviceinfo] remove Buteo::SyncDBusConnection from DeviceInfoProvider

Apparently Buteo::SyncDBusConnection exists to address QTBUG-11413.
However, analysis of the above bugreport indicates that there is
no bug and calling QDBusConnection::systemBus() before additional
threads are created, as msyncd already does, is enough to prevent
any race issues.
[tests] make StorageFactory_test compile and pass

Removed some obsolete test cases.
[tests] add testGetDevicePropValueAfterObjectInfoChanged()

This test case covers the bug fixed in 2bb60691:
 [storage] discard object's all cached properties on ObjectInfoChanged