MojDbShardEngine: fix kind indexes

:Release Notes:
Fix kind indexes for MojDbShardEngine

:Detailed Notes:
- Fix kind indexes for MojDbShardEngine
- Fix isExist function
- Refactoring of returning values
- Improve check for internal pointers

:Testing Performed:

:QA Notes:

:Issues Address:

Open-webOS-DCO-1.0-Signed-off-by: Maksym Sditanov <maxim.sditanov@lge.com>

Change-Id: I77080fcd70ecaef6d872a6489447776eb23ba2d5
Reviewed-on: https://g2g.palm.com/3230
Reviewed-by: Build Verification
Reviewed-by: Roger Stringer <roger.stringer@lge.com>
Tested-by: Roger Stringer <roger.stringer@lge.com>