mod_http_oauth2: Always show early errors to user Before having validated the client_id, communicating an error back to the client via redirect would make this an open redirect, so we may just as well skip past that logic, and especially the warning log message.

This module lets you block connections to any remote servers not on a
whitelist.

``` {.lua}
modules_enabled = {
    -- other modules --
    "s2s_whitelist",

}
s2s_whitelist = {
    "example.org",
}
```