tox: Tox/Pyenv failure upon creating virtualenv

even if skip_missing_interpreters=True

This didn’t use to be the case. The exact error message is:

 ERROR: Error creating virtualenv. Note that some special characters (e.g. ':' and unicode symbols) in paths are not supported by virtualenv. Error details: InvocationError('Failed to get version_info for python3.5: b"pyenv: python3.5: command not found\\n\\nThe `python3.5\' command exists in these Python versions:\\n  3.5\\n  3.5.3\\n\\n"',)

See:

https://travis-ci.org/berdario/pew/jobs/281757929

I unfortunately don’t have time to investigate much into it, but the TravisCI build link should have everything you need: you can see that previous builds passed just fine when the interpreter didn’t exist, and in the repository you can find the tox.ini