Allow localized names for Virtual Switch

[gbraad]

Fixes #4429

This change allows for use of localized names for Virtual Switches. This is for instance needed when dealing with the "Default Switch" by name, as lozalized versions of Windows use names like; "Przełącznik domyślny"

[GordonTheTurtle]

Please sign your commits following these rules:
https://github.com/moby/moby/blob/master/CONTRIBUTING.md#sign-your-work
The easiest way to do this is to amend the last commit:

$ git clone -b "localized-switches" git@github.com:gbraad/docker-machine.git somewhere
$ cd somewhere
$ git commit --amend -s --no-edit
$ git push -f

Amending updates the existing PR. You DO NOT need to open a new one.