This fixes a bug in coverage logging that's been around since the logging was
introduced.
Github-Pull: #11277
Rebased-From: 505530c6cffeab8dc1f75f54ae0dfdcdb55d370b
Change AuthServiceProxyWrapper.__getattr__ to only wrap proxied attributes, not
real attributes. This way AuthServiceProxyWrapper can continue logging RPC
calls without complicating other object usages, and special case handling for
the .url property can be dropped.
Github-Pull: #11277
Rebased-From: e02007aade3d449f030fe5c8b12beddd7df1b232