Add containerdVersion flag

Add version flag that only prints the static version for the binary.

This commit does not include build details for containers since
Makefile does not build them.

Closes #8

Signed-off-by: Christopher M. Luciano <cmluciano@us.ibm.com>

cmd/cri-containerd/cri_containerd.go

@@ -17,11 +17,14 @@ limitations under the License.
 package main
 
 import (
+	"os"
+
 	"github.com/golang/glog"
 	"github.com/spf13/pflag"
 
 	"github.com/kubernetes-incubator/cri-containerd/cmd/cri-containerd/options"
 	"github.com/kubernetes-incubator/cri-containerd/pkg/server"
+	"github.com/kubernetes-incubator/cri-containerd/pkg/version"
 )
 
 func main() {
@@ -29,6 +32,11 @@ func main() {
 	o.AddFlags(pflag.CommandLine)
 	options.InitFlags()
 
+	if o.CRIContainerdVersion {
+		version.PrintVersion()
+		os.Exit(0)
+	}
+
 	glog.V(2).Infof("Connect to containerd socket %q with timeout %v", o.ContainerdSocketPath, o.ContainerdConnectionTimeout)
 	conn, err := server.ConnectToContainerd(o.ContainerdSocketPath, o.ContainerdConnectionTimeout)
 	if err != nil {