fix tests and defs bug for category descriptions

:Release Notes:
Fixed an issue met when definitions per category used but no definitions for
specific schemas in that category.

:Detailed Notes:
- added test to reproduce bug
- added proper handling of missing definitions in call/reply schemas
- fixed other tests that built wrong category schema

:Testing Performed:
unit/integration tests under desktop

:QA Notes:

:Issues Addressed:
[BHV-1592] Implement optional validation of received payload

Open-webOS-DCO-1.0-Signed-off-by: Nikolay Orliuk <nikolay.orliuk@lge.com>

Change-Id: Icbda7a49dda3d7f01f14280586ed6dd1898bef41
Reviewed-on: https://g2g.palm.com/5666
Reviewed-by: DCO Verification
Reviewed-by: Nikolay Orliuk <nikolay.orliuk@lge.com>
Tested-by: Nikolay Orliuk <nikolay.orliuk@lge.com>
Reviewed-by: Oleksii Rudenko <oleksii.rudenko@lge.com>
Reviewed-by: Anatolii Sakhnik <anatolii.sakhnik@lge.com>