Because pkgmgr-info.service has a default OOMScore
if there is insufficient memory in the system
the pkgmgr-info.service can be a victim with a high priority
To prevent this, apply OOMScore to -100
Change-Id: Ic48662f207a0208d358a1c3f813ab3a8c8864602 Signed-off-by: Ilho Kim <ilho159.kim@samsung.com>