If $SSH_AUTH_SOCK is set, SSH keys are used for authentication

[SergiiDmytruk]

Despite #39, operations over SSH wait 30 seconds and then ask for a passphrase of the SSH key. Not providing a passphrase leads to failures, meaning that you must not forget to wait for the prompt.

I've tracked this down to $SSH_AUTH_SOCK being set. Unsetting it prevents the issue from happening. gpg-agent is what caches the SSH key and it works fine, so it's not like that socket isn't functional. Not sure how some this script picks up on this environment variable, must be some of the dependencies.

Now that I have a workaround, it's not a big deal, but someone else might hit this as well, so worth documenting.