Remove hard dependency on keyring

[BenjamenMeyer]

keyring now as a hard dependency on secretstorage which has a hard dependency on dbus-python and on Debian python-dbus (a system level package). This does not make sense for WSGI apps where the keyring will never be used, thus having a hard dependency on keyring while nice for the command-line interface is now problematic for APIs.

If keyring is installed, then use it. But if not, then please disable storage.

Filing this here in case keyring doesn't resolve this per jaraco/keyring#236; issues has already been field with secretstorage twice and they refuse to break the hard dependency at that level.

[BenjamenMeyer]

Initially filed this as being directly related to secretstorage as I had thought that was the being directly pulled in by pyrax, however it's a dependency of a dependency so I updated this accordingly.

[briancurtin]

Do you want this to depend on whether keyring ends up making their change, or do you want to just change this anyway?

[BenjamenMeyer]

@briancurtin having it depend on whether or not keyring makes the change at their level is okay with me

Either way, pyrax should not fail to install if dbus is not available.