Burminate v1auth

This closes #2602

v1auth was created to account for the differences in status code between
the v1 and v2_alpha revisions of the protocol (401 vs 403 for invalid
tokens). However since those protocols were merged, this makes the r0
version/endpoint internally inconsistent, and violates the
specification for the r0 endpoint.

This might break clients that rely on this inconsistency with the
specification. This is said to affect the legacy angular reference
client. However, I feel that restoring parity with the spec is more
important. Either way, it is critical to inform developers about this
change, in case they rely on the illegal behaviour.

Signed-off-by: Adrian Tschira <nota@notafile.com>