[Minor] Further simplify conditionals

[Minor] Further simplify conditionals

src/plugins/lua/greylist.lua

@@ -323,7 +323,7 @@ local function greylist_set(task)
      rspamd_logger.infox(task, 'got error while connecting to redis: %1', upstream:get_addr())
      upstream:fail()
     end
-  elseif do_greylisting or (do_greylisting_required and do_greylisting_required == "1") then
+  elseif do_greylisting or do_greylisting_required then
     local t = tostring(math.floor(rspamd_util.get_time()))
     local end_time = rspamd_util.time_to_string(t + settings['timeout'])
     rspamd_logger.infox(task, 'greylisted until "%s", new record', end_time)