Code review comment for lp:~dpigott/lava-scheduler-tool/fix821400-add-token-file

Apologies for not commenting earlier. I really thought I had :/

This change means that the keyring backend will never be used! I don't think that's right. I've made some changes in https://code.launchpad.net/~dpigott/lava-scheduler-tool/fix821400-add-token-file (extracting fiddling around for a token to a function, and use the keyring backend if no token is otherwise supplied). Perhaps a function that gets an AuthenticatingServerProxy given a server url and a token file name (or even an argparse options object) needs to be added to lava-tool...