qa/admin/check-vm: send all warnings to stderr
qa/admin/check-vm: send all warnings to stderr

So package-tool-of-choice `check-vm -p` works properly.

adfernandes/pcp,adfernandes/pcp,adfernandes/pcp,adfernandes/pcp,adfernandes/pcp,adfernandes/pcp,adfernandes/pcp,adfernandes/pcp