Update shim for exec

Signed-off-by: Michael Crosby <crosbymichael@gmail.com>

supervisor/update.go

@@ -27,17 +27,17 @@ func (h *UpdateEvent) Handle(e *Event) error {
 		}
 	}
 	if e.Signal != nil {
-		/*
-			// signal the pid1/main process of the container
-			processes, err := container.Processes()
-			if err != nil {
-				return err
+		// signal the pid1/main process of the container
+		processes, err := container.Processes()
+		if err != nil {
+			return err
+		}
+		for _, p := range processes {
+			if p.ID() == runtime.InitProcessID {
+				return p.Signal(e.Signal)
 			}
-			if len(processes) == 0 {
-				return ErrProcessNotFound
-			}
-			return processes[0].Signal(e.Signal)
-		*/
+		}
+		return ErrProcessNotFound
 	}
 	return nil
 }