Enable c++11

:Release Notes:
Add C++11 flag into cmake file

:Detailed Notes:

:Testing Performed:

:QA Notes:

:Issues Addressed:

[BHV-2215] enable c++11 in db8

Open-webOS-DCO-1.0-Signed-off-by: Olexandr Solomakha <oleksander.solomakha@lge.com>

Change-Id: I31732c053ffebaad26de4b50916d7f401f3c69a3
Reviewed-on: https://g2g.palm.com/5250
Reviewed-by: DCO Verification
Tested-by: Olexandr Solomakha <oleksander.solomakha@lge.com>
Reviewed-by: Oleg Yablokov <oleg.yablokov@lge.com>