Print out the pid of iomux-spawn's child
Print out the pid of iomux-spawn's child

Change-Id: Id21e8c64a66699d4f845b9c20a0391897263154d

cloudfoundry-incubator/garden,tsaleh/garden,tangfeixiong/garden,cloudfoundry-incubator/garden-linux,shashidharatd/garden-linux,shashidharatd/garden-linux,cloudfoundry-incubator/garden-linux,tsaleh/garden,shashidharatd/garden-linux,tangfeixiong/garden,savaki/garden,shashidharatd/garden-linux,savaki/garden,cloudfoundry-incubator/garden-linux,cloudfoundry-incubator/garden