Implement a NoOp DrmManagerClientImpl when no DRM service exists

Change-Id: Ib06f429102a51c540c8132f3397130328279e03a
diff --git a/drm/libdrmframework/DrmManagerClient.cpp b/drm/libdrmframework/DrmManagerClient.cpp
index ea30d01..440dd91 100644
--- a/drm/libdrmframework/DrmManagerClient.cpp
+++ b/drm/libdrmframework/DrmManagerClient.cpp
@@ -29,7 +29,7 @@
 }
 
 DrmManagerClient::~DrmManagerClient() {
-    DrmManagerClientImpl::remove(mUniqueId);
+    mDrmManagerClientImpl->remove(mUniqueId);
     mDrmManagerClientImpl->removeClient(mUniqueId);
     mDrmManagerClientImpl->setOnInfoListener(mUniqueId, NULL);
 }