TS-1651 raw disk cache disabled when system start

raw disk cache disabled when system start

we force a initgroups before cop spawn the manager process, and
when manager spawn the server too.
This is a patch fix for the init groups, without the fix, you
will get permission issue when your server reboots. --zym

test/review: zym, igalic, jpeach, humbedooh
backport: igalic
propose TS-1609