mod_http_admin_api: metrics: Filter out a value that is commonly nan at startup The upload bytes count is typically nan at startup, which cannot legally be encoded in JSON. I haven't assessed whether any other metrics might emit nan under other circumstances, but this fixes the most visible issue right now.

local count_registering = module:measure("user_registering", "rate");
local count_registered = module:measure("user_registered", "rate");

module:hook("user-registering", function ()
	count_registering();
end);

module:hook("user-registered", function ()
	count_registered();
end);