Replace spaces by underscores when forging module name

Plugins can provide a module to be called to extract extra information
at authentication time. The module name is based on the protocol used. Some
protocols have a space in their name, like "Web MQTT", so spaces in such
cases must be replaced by underscores to come up with a valid Erlang
module name.

[#166271318]

References #1767

(cherry picked from commit 2f958a0)

Author: acogoluegnes

src/rabbit_direct.erl

@@ -133,7 +133,9 @@ extract_protocol(Infos) ->
 
 maybe_call_connection_info_module(Protocol, Creds, VHost, Pid, Infos) ->
     Module = rabbit_data_coercion:to_atom(string:to_lower(
-        "rabbit_" ++ rabbit_data_coercion:to_list(Protocol) ++ "_connection_info")
+        "rabbit_" ++
+        lists:flatten(string:replace(rabbit_data_coercion:to_list(Protocol), " ", "_", all)) ++
+        "_connection_info")
     ),
     Args = [Creds, VHost, Pid, Infos],
     code_server_cache:maybe_call_mfa(Module, additional_authn_params, Args, []).