Release mDrmManagerClient in PduPersister release

In Mms test log we found StrictMode printed out DrmManagerClient was
not released, it was created in PduPersister constructor.

To fix this problem, call mDrmManagerClient.release in PduPersister.
release.

Bug: 143230740
Test: Edit and send MMS, not print this log again.
Change-Id: If3318c8e77d6272b9d83af57d910951055356d99
diff --git a/telephony/common/com/google/android/mms/pdu/PduPersister.java b/telephony/common/com/google/android/mms/pdu/PduPersister.java
index 93f3065..95ae409 100755
--- a/telephony/common/com/google/android/mms/pdu/PduPersister.java
+++ b/telephony/common/com/google/android/mms/pdu/PduPersister.java
@@ -1548,6 +1548,7 @@
     public void release() {
         Uri uri = Uri.parse(TEMPORARY_DRM_OBJECT_URI);
         SqliteWrapper.delete(mContext, mContentResolver, uri, null, null);
+        mDrmManagerClient.release();
     }
 
     /**