Make sure that zombie processes are cleaned up

[alextoulps]

As there is a usage of cmd.Start() ensure that Wait() will be called to clean up resources.
Currently in a running app that might poll for the status, this causes a leak.

[ovoschnoi-salat]

You put it in a wrong place, you should ensure calling Wait only after Start is called without errors

[alextoulps]

You put it in a wrong place, you should ensure calling Wait only after Start is called without errors

Yeah was also debating if it should be right after the Start but since it is a defer and the implementation of Wait will in worst case return an error that will be ignored, i wanted to follow the practice of ensuring defer call right after the initialisation of the resource that needs to ensure clean up of resources.