[win] determining user status (admin) depends on English version

[icebob]

On Windows 7, the nanobox run command returns with an error:

--------------------------------------------------------------------------------
+ ERROR:
+ Nanobox is designed to run as a standard user (non root)
+ Please run all nanobox commands as a non privileged user
--------------------------------------------------------------------------------

The reason is that the net session command returns with different message as Win 10. There are no entries in the list. Relevant code: https://github.com/nanobox-io/nanobox/blob/master/util/util_windows.go#L29

Otherwise this solution is not too good because this message is localized, so it is working only on English Win 10.

[danhunsaker]

Windows 7 is actually unsupported, so any bugs with using it are unlikely to be addressed, and often even expected.