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
diff --git a/drm/libdrmframework/DrmManagerClient.cpp b/drm/libdrmframework/DrmManagerClient.cpp
index fa3d52a..8bb00c3 100644
--- a/drm/libdrmframework/DrmManagerClient.cpp
+++ b/drm/libdrmframework/DrmManagerClient.cpp
@@ -31,6 +31,7 @@
 DrmManagerClient::~DrmManagerClient() {
     DrmManagerClientImpl::remove(mUniqueId);
     mDrmManagerClientImpl->removeClient(mUniqueId);
+    mDrmManagerClientImpl->setOnInfoListener(mUniqueId, NULL);
     delete mDrmManagerClientImpl; mDrmManagerClientImpl = NULL;
 }