DRM Framework bug fixes.

- Make sure to clean-up obsolete listeners.
- Close cursor after using it.
- Add virtual destructor to the base class of OnInfoListener.

Changes are made by SEMC and Sony.

Change-Id: Ibb6dd625ef48e3597188f0d7c90f9d4c780b6139

drm/libdrmframework/DrmManagerClient.cpp

@@ -31,6 +31,7 @@ DrmManagerClient::DrmManagerClient():
 DrmManagerClient::~DrmManagerClient() {
     DrmManagerClientImpl::remove(mUniqueId);
     mDrmManagerClientImpl->removeClient(mUniqueId);
+    mDrmManagerClientImpl->setOnInfoListener(mUniqueId, NULL);
     delete mDrmManagerClientImpl; mDrmManagerClientImpl = NULL;
 }