plugins: correctly output build version, cosmetic cleanups

Now that libcni has the ability to print a version message, plumb it
through correctly.

While we're at it,
- fix import paths
- run gofmt
- add some more comments to sample
- add container runtime swappability for release

plugins/main/ptp/ptp.go

@@ -22,16 +22,19 @@ import (
 	"os"
 	"runtime"
 
+	"github.com/j-keck/arping"
+	"github.com/vishvananda/netlink"
+
 	"github.com/containernetworking/cni/pkg/skel"
 	"github.com/containernetworking/cni/pkg/types"
 	"github.com/containernetworking/cni/pkg/types/current"
 	"github.com/containernetworking/cni/pkg/version"
+
 	"github.com/containernetworking/plugins/pkg/ip"
 	"github.com/containernetworking/plugins/pkg/ipam"
 	"github.com/containernetworking/plugins/pkg/ns"
 	"github.com/containernetworking/plugins/pkg/utils"
-	"github.com/j-keck/arping"
-	"github.com/vishvananda/netlink"
+	bv "github.com/containernetworking/plugins/pkg/utils/buildversion"
 )
 
 func init() {
@@ -110,7 +113,7 @@ func setupContainerVeth(netns ns.NetNS, ifName string, mtu int, pr *current.Resu
 			}
 
 			for _, r := range []netlink.Route{
-				netlink.Route{
+				{
 					LinkIndex: contVeth.Index,
 					Dst: &net.IPNet{
 						IP:   ipc.Gateway,
@@ -119,7 +122,7 @@ func setupContainerVeth(netns ns.NetNS, ifName string, mtu int, pr *current.Resu
 					Scope: netlink.SCOPE_LINK,
 					Src:   ipc.Address.IP,
 				},
-				netlink.Route{
+				{
 					LinkIndex: contVeth.Index,
 					Dst: &net.IPNet{
 						IP:   ipc.Address.IP.Mask(ipc.Address.Mask),
@@ -285,8 +288,7 @@ func cmdDel(args *skel.CmdArgs) error {
 }
 
 func main() {
-	// TODO: implement plugin version
-	skel.PluginMain(cmdAdd, cmdCheck, cmdDel, version.All, "TODO")
+	skel.PluginMain(cmdAdd, cmdCheck, cmdDel, version.All, bv.BuildString("ptp"))
 }
 
 func cmdCheck(args *skel.CmdArgs) error {