Move most of OCI spec options to common builder

Signed-off-by: Maksym Pavlenko <pavlenko.maksym@gmail.com>

pkg/cri/sbserver/helpers_linux.go

@@ -40,8 +40,6 @@ import (
 )
 
 const (
-	// relativeRootfsPath is the rootfs path relative to bundle path.
-	relativeRootfsPath = "rootfs"
 	// devShm is the default path of /dev/shm.
 	devShm = "/dev/shm"
 	// etcHosts is the default path of /etc/hosts file.
@@ -50,8 +48,6 @@ const (
 	etcHostname = "/etc/hostname"
 	// resolvConfPath is the abs path of resolv.conf on host or container.
 	resolvConfPath = "/etc/resolv.conf"
-	// hostnameEnv is the key for HOSTNAME env.
-	hostnameEnv = "HOSTNAME"
 )
 
 // getCgroupsPath generates container cgroups path.