fixed admin check for token verification

resources/prosody-plugins/mod_token_verification.lua

 local log = module._log;
 local host = module.host;
 local st = require "util.stanza";
-local is_admin = require "core.usermanager".is_admin;
+local um_is_admin = require "core.usermanager".is_admin;
 
 
+local function is_admin(jid)
+    return um_is_admin(jid, host);
+end
+
 local parentHostName = string.gmatch(tostring(host), "%w+.(%w.+)")();
 if parentHostName == nil then
 	log("error", "Failed to start - unable to get parent hostname");