Merge "Remove NPE in VoipCallTransactionResult" into main

    public static final int RESULT_SUCCEED = 0;

    public static final int RESULT_FAILED = 1;

    private int mResult;

    private String mMessage;

    private Call mCall;

    private final int mResult;

    private final String mMessage;

    private final Call mCall;

    public VoipCallTransactionResult(int result, String message) {

        mResult = result;

        mMessage = message;

        mCall = null;

    }

    public VoipCallTransactionResult(int result, Call call, String message) {

                append("{ VoipCallTransactionResult: [mResult: ").

                append(mResult).

                append("], [mCall: ").

                append(mCall.toString()).

                append((mCall != null) ? mCall : "null").

                append("], [mMessage=").

                append(mMessage).append("]  }").toString();

    }