Switch to HexEncoding from ByteStringUtils

package android.mtp;

import com.android.internal.util.Preconditions;

import android.content.Context;

import android.content.SharedPreferences;

import android.util.ByteStringUtils;

import com.android.internal.util.Preconditions;

import libcore.util.HexEncoding;

import java.io.FileDescriptor;

import java.util.Random;

        byte[] randomBytes = new byte[sID_LEN_BYTES];

        randomVal.nextBytes(randomBytes);

        return ByteStringUtils.toHexString(randomBytes);

        return HexEncoding.encodeToString(randomBytes);

    }

    public void start() {