Fix setting process for default Locale

:Release Notes:
Fix ICU setting default locale

:Detailed Notes:
Fix MojDB setting default locale
Add checking for error code from ICU when default locale setting
Make test_db_core temporary directory to be more accurate
Fix include guard for MojDbLunaServiceDb.h

:Testing Performed:
Compiled and tested locally

:QA Notes:

:Issues Addressed:
[GF-35815] gtest_db_core has 5 failures

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

Change-Id: I9838a8a90c14a83e13a8ef9e6ba09c151e1a16f9
Reviewed-on: https://g2g.palm.com/3876
Reviewed-by: Build Verification
Tested-by: Maksym Sditanov <maxim.sditanov@lge.com>
Reviewed-by: Nikolay Orliuk <nikolay.orliuk@lge.com>
Reviewed-by: Maksym Sditanov <maxim.sditanov@lge.com>