Merge "Close MTP database when MtpServer's thread is terminated."

public class MtpServer implements Runnable {

    private long mNativeContext; // accessed by native methods

    private final MtpDatabase mDatabase;

    static {

        System.loadLibrary("media_jni");

    }

    public MtpServer(MtpDatabase database, boolean usePtp) {

        mDatabase = database;

        native_setup(database, usePtp);

        database.setServer(this);

    }

    public void run() {

        native_run();

        native_cleanup();

        mDatabase.close();

    }

    public void sendObjectAdded(int handle) {