mod_roster_command: Fix subscription when the "user JID" is a bare domain. Do not attempt to update the roster when the user is bare domain (e.g. a component), since they don't have rosters and the attempt results in an error: $ prosodyctl mod_roster_command subscribe proxy.example.com contact@example.com xxxxxxxxxxFailed to execute command: Error: /usr/lib/prosody/core/rostermanager.lua:104: attempt to concatenate local 'username' (a nil value) stack traceback: /usr/lib/prosody/core/rostermanager.lua:104: in function 'load_roster' /usr/lib/prosody/core/rostermanager.lua:305: in function 'set_contact_pending_out' mod_roster_command.lua:44: in function 'subscribe'

module:set_global();

local traceback = require "util.debug".traceback;

require"util.signal".signal(module:get_option_string(module.name, "SIGUSR1"), function ()
	module:log("info", "Received SIGUSR1, writing traceback");
	local f = io.open(prosody.paths.data.."/traceback.txt", "a+");
	f:write(traceback(), "\n");
	f:close();
end);