nativepowerman: add "wakelock" GID for wakelock sysfs access

nativepowerman must now run under group AID_WAKELOCK to access the sysfs
wakelock interface.

Bug: 26348967
Bug: 25864142
Change-Id: I1603b5a91c450b32d7d7ff9a6662fcdc1f6b4fed
1 file changed