Change start condition of db8

:Release Notes:
Change start condition of db8

:Detailed Notes:
In order to launch webapp faster, we need to start WAM ASAP.

Current dependency of WAM is ...

- DB8 --> SettingService --> SettingService-ready --> WAM

Current boot seq for db8 is ...

- init-boot-done --> SAM --> BootD --> minimal-boot-done --> DB8

If we change db8 starting condition from 'minimal-boot-done' to
'init-boot-done', WAM can be start more early.

:Testing Performed:
Build #382 + this commit : db8 works fine.

:QA Notes:

:Issues Addressed:
[GF-44168] [Boottime] Optimize boot sequence

Open-webOS-DCO-1.0-Signed-off-by: Sangwoo Kang <sangwoo82.kang@lge.com>

Change-Id: I2110775373150d78f73dc6bd59e7a9978dfcaa9b
Reviewed-on: https://g2g.palm.com/3795
Reviewed-by: Build Verification
Reviewed-by: Maksym Sditanov <maxim.sditanov@lge.com>
Tested-by: Maksym Sditanov <maxim.sditanov@lge.com>