Remove unused function in systemd cgroup
Remove unused function in systemd cgroup

Signed-off-by: Qiang Huang <488e06933c295c76472a67dbc6657ac40a756953@huawei.com>

avagin/runc,rhatdan/runc,sunyuan3/runc,estesp/runc,mYmNeo/runc,justincormack/runc,laijs/runc,WeiZhang555/runc,crosbymichael/runc,sunyuan3/runc,vbatts/runc,hqhq/runc,avagin/runc,rhatdan/runc,opencontainers/runc,adrianreber/runc,wking/runc,crosbymichael/runc,mheon/runc,rajasec/runc,xiaochenshen/runc,vbatts/runc,laijs/runc,opencontainers/runc,adrianreber/runc,dqminh/runc,shishir-a412ed/runc,cyphar/runc,coolljt0725/runc,mheon/runc,sunyuan3/runc,vbatts/runc,wking/runc,xiaochenshen/runc,WeiZhang555/runc,dqminh/runc,dqminh/runc,coolljt0725/runc,adrianreber/runc,justincormack/runc,mheon/runc,rajasec/runc,hqhq/runc,rhatdan/runc,cloudfoundry-incubator/runc,stefanberger/runc,mYmNeo/runc,mikebrow/runc,mikebrow/runc,cloudfoundry-incubator/runc,cloudfoundry-incubator/runc,cyphar/runc,opencontainers/runc,justincormack/runc,dqminh/runc,kolyshkin/runc,kolyshkin/runc,estesp/runc,wking/runc,hqhq/runc,shishir-a412ed/runc,crosbymichael/runc,WeiZhang555/runc,stefanberger/runc,xiaochenshen/runc,cyphar/runc,kolyshkin/runc,docker/runc,docker/runc,stefanberger/runc,laijs/runc,opencontainers/runc,shishir-a412ed/runc,kolyshkin/runc,mikebrow/runc,estesp/runc,mYmNeo/runc,avagin/runc,docker/runc,rhatdan/runc,rajasec/runc,coolljt0725/runc