Make sure signalAllProcesses is invoked in the function of destroy

It's expect that signalAllProcesses is invoked when container shares
pid namespace. share pid ns contains the following conditions:

{
    // no specify pid ns
}
{
    "type": "pid",
    "path": "/proc/${num}/ns/pid"
}

Signed-off-by: Shukui Yang <[email protected]>
Signed-off-by: Shukui Yang <[email protected]>

libcontainer/state_linux.go

@@ -38,7 +38,8 @@ type containerState interface {
 }
 
 func destroy(c *linuxContainer) error {
-	if !c.config.Namespaces.Contains(configs.NEWPID) {
+	if !c.config.Namespaces.Contains(configs.NEWPID) ||
+		c.config.Namespaces.PathOf(configs.NEWPID) != "" {
 		if err := signalAllProcesses(c.cgroupManager, unix.SIGKILL); err != nil {
 			logrus.Warn(err)
 		}