Rather than occasionally playing catch-up until the wait_for methods are
removed from the base Proxy in 1.0, we can temporarily ignore those two
names. This allows us to make the doc build fail if undocumented proxy
methods occur.
After 1.0 we should remove the special cases for wait_for names, but
leave warnings_as_errors on.
Change-Id: I8fe41ed639ec318a18db3022371b52382c53aa99
b835543f65