Command line can be nil in Win32_Process

[jsoriano]

Command line can be nil, what produces errors like:

wmi: cannot load field "CommandLine" into a "string": unsupported type (<nil>)`

Change command line in receiving struct to be a pointer, so it can be converted by wmi if it receives a nil.

[andrewkroh]

LGTM.

I should note that we have a way to bypass WMI to get this information in go-sysinfo. It uses a system call so it's a lot faster than WMI. For Metricbeat we might want to consider this option for getting the args.

[jsoriano]

Oh, interesting, I'll try to replace gosigar by go-sysinfo for processes collection in metricbeat.