lua: use notice level for log()

By default, notice level is set. Thus, if users want to use log() in the same way as pre-5.4, they'd have to increase the log level. This bumps the log level of log() function to keep the same behavior.

daemon/lua/sandbox.lua.in

@@ -69,7 +69,7 @@ function log_debug(grp, fmt, ...)
 end
 
 function log(fmt, ...)
-	log_info(ffi.C.LOG_GRP_MODULE, fmt, ...)
+	log_notice(ffi.C.LOG_GRP_MODULE, fmt, ...)
 end
 
 -- Resolver bindings