server: change back to use rancher-volume for mount
server: change back to use rancher-volume for mount

Now the namespace is hardcoded to host pid 1 namespace, which should be right
both natively and in the container.

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