MINOR: proxy: disable warnings for internal proxies

The internal proxies should be part of the proxies list, because of
this, the check_config_validity() fonction could emit warnings about
these proxies.

This patch disables 3 startup warnings for internal proxies:

- "has no 'bind' directive" (this one was already ignored for the CLI
frontend, but we made it generic instead)
- "missing timeouts"
- "log format ignored"
1 file changed