Fix issue #4424 - Pre-create check: "Hyper-V PowerShell Module is not available"

[beppler]

Pull request #4404 adds the ability to run Hyper-V driver when VMware PowerCLI is installed, but it make the pre-create check for Hyper-V module fail.

This corrects the test as indicated as best solution on #4424.

[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 "4424-powershell-module-not-available" git@github.com:beppler/machine.git somewhere
$ cd somewhere
$ git rebase -i HEAD~842357010440
editor opens
change each 'pick' to 'edit'
save the file and quit
$ git commit --amend -s --no-edit
$ git rebase --continue # and repeat the amend for each commit
$ git push -f

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

[dgageot]

LGTM

[gbraad]

Can this be tagged as a new (minor) release? As this fixes a breaking change...

Ref: minishift/minishift#2159 (comment)

[krzysztofantczak]

Quick hack for people in hurry. Editing docker-machine binary file and replacing (ie. with vim or other editor - kind of - safe for binary files) :%s/Hyper-V/hyper-v/g works.

[gbraad]

I'd rather not choose to go for local patches, as this will result in issues later on.
At the moment we pull a revision ... waiting for a tag

[mtudor]

Although hacky, @krzysztofantczak suggestion did work for me (on Windows, C:\Program Files\Docker\Docker\resources\bin\docker-machine.exe - make a backup of the file first) if anyone is in a bind and needs a quick fix; at your own risk and bearing in mind the warning from @gbraad.