SDL should respond "IGNORED" with correct result code for UnSubscribeVehicleData in case vi interface isn't available

[KhrystynaDubovyk]

Occurence:
Always

Environment
Branch: (https://github.com/smartdevicelink/sdl_core/)
branch: "release/4.2.0"
commit id: a6c32b45832653d6b851be9b19355fa35f377e07
HMI: HTML5
ATF version: 2.2
ATF repo: https://github.com/smartdevicelink/sdl_atf/
ATF branch: 962e1eff8664d97af5e59ec4e22f39b9ea76f5eb
Scripts repo: https://github.com/CustomSDL/sdl_atf_test_scripts/tree/OS_DRAFT
Scripts branch: 18cce42
OS: Ubuntu 14.04.01
Transport: Wi-Fi
Mobile device: -
Mobile OS: -
Mobile App version: -
Mobile App type (media/non-media/navi/any): any
Virtual Machine using (yes/no): no

Preconditions:

1. Move IsReady_Template folder into sdl_atf\user_modules
2. SubscribeVehicleData and UnSubscribeVehicleData are allowed in PT

Steps to reproduce:
Or: (Go to atf folder -> Run command: ./start.sh ../ATF_VehicleInfo_IsReady_available_false_SingleRPC.lua)

1. RegisterApp incase HMI does not respond
2. Activate app
3. Send SubscribeVehicleData with gps = true
4. Send UnSubscribeVehicleData with gps = true
   Actual result:
   SDL respond "
   {success = true, resultCode = "IGNORED", info = "Already subscribed on some provided VehicleData."}
   ".
   Expected result:
   SDL should respond "
   {success = false, resultCode = "IGNORED", info = "Some provided VehicleData was not subscribed."}
   " code to mobile app.