Heroku.from_key is silently overridden by .netrc

[gabrtv]

Reproduce Steps

Login using Heroku CLI as user1

gabriel@delta:~$ heroku login
Enter your Heroku credentials.
Email: user1@opdemand.com
Password (typing will be hidden): 
Authentication successful.

~/.netrc file is updated per usual.

Use Heroku.py to instantiate a session as user2

>>> h=heroku.from_key('key-for-user2')
>>> h.keys
[<key 'user1@user1s-machine.local'>]

D'oh it's using a session from user1 via .netrc even though we provided user2's key.

Worst part is it doesn't warn you. It just silently proceeds as the wrong user.