record pid of exec'd process

Signed-off-by: Antonio Murdaca <runcom@redhat.com>
Upstream-commit: 18083481361a4053d1081a201120a916239fc0ed
Component: engine

components/engine/daemon/exec/exec.go

@@ -28,6 +28,7 @@ type Config struct {
 	Privileged  bool
 	User        string
 	Env         []string
+	Pid         int
 }
 
 // NewConfig initializes the a new exec configuration