Revert "Merge pull request #853 from AkihiroSuda/check-rootfs"

This reverts commit c1530b5b76, reversing
changes made to 3695ba77bb.

Signed-off-by: Kenfe-Mickael Laventure <mickael.laventure@gmail.com>

linux/shim/init.go

@@ -11,7 +11,6 @@ import (
 	"syscall"
 	"time"
 
-	"github.com/pkg/errors"
 	"golang.org/x/sys/unix"
 
 	"github.com/containerd/console"
@@ -37,9 +36,6 @@ type initProcess struct {
 }
 
 func newInitProcess(context context.Context, path string, r *shimapi.CreateRequest) (*initProcess, error) {
-	if len(r.Rootfs) == 0 {
-		return nil, errors.New("no rootfs was specified")
-	}
 	for _, rm := range r.Rootfs {
 		m := &containerd.Mount{
 			Type:    rm.Type,