libcutils: only change cgroup when fd is initialized [ DO NOT MERGE ]

This is to avoid failues on setting non-exist cgroup

Bug: 34193533
Test: on marlin
Change-Id: I619dcba332fda9ec421df811745cf10311beddd3
(cherry picked from commit e46aae223626432bde7d4e95818e8394664c6c02)
1 file changed