oc >= 3.7.0-rc.0 cannot talk to OpenShift servers < 3.6.0-rc.0

Attempting to log in to an OpenShift server running any version prior to 3.6.0-rc.0 using oc with version of 3.7.0-rc.0 or newer fails with an error.

Version

oc v3.7.0+7ed6862
kubernetes v1.7.6+a08f5eeb62
features: Basic-Auth

Server [REDACTED]
openshift v1.3.3
kubernetes v1.3.0+52492b4

Steps To Reproduce

1. Set up an OpenShift server running version 1.5.1 or older
2. Using oc version 3.7.0, run oc login

Current Result

scapeless:~ elyscape$ oc login [REDACTED]
error: Missing configuration - verify you have provided the correct host and port and that the server is currently running.
error: Missing configuration

Expected Result

Login is able to proceed.

Additional Information

The issue stems from this commit, which added PKCE support to oc. Unfortunately, the implementation now requires that the server offers a document from the OAuth metadata endpoint (/.well-known/oauth-authorization-server). That endpoint was added in this commit, which first shipped in 3.6.0-rc.0. Ideally, oc should be able to fall back to the old behavior if the OAuth metadata endpoint is not present.