logging: make sure log output to either file or stderr
logging: make sure log output to either file or stderr

Output to stdio would result in fail to parse the json

jinuxstyle/convoy,rancher/rancher-volume,dx9/convoy,nickvanw/convoy,mehulsbhatt/convoy,rancherio/rancher-volume,rancherio/rancher-volume,rancherio/volmgr,medallia/convoy,dx9/convoy,moypray/convoy,jinuxstyle/convoy,rancher/rancher-volume,rancherio/volmgr,aruneli/convoy,dx9/convoy,aruneli/convoy,aruneli/convoy,nickvanw/convoy,nickvanw/convoy,medallia/convoy,rancher/convoy,rancher/convoy,jinuxstyle/convoy,mehulsbhatt/convoy,medallia/convoy,rancherio/rancher-volume,moypray/convoy,rancher/rancher-volume,mehulsbhatt/convoy,moypray/convoy,rancher/convoy,rancherio/volmgr