Fix usage of settings in Lua 5.1

Without 2eb0af0 I get:

<pre>
Jul  2 13:44:06 durandal lsyncd: Normal, recursive startup rsync: /home/plouj/ -> /media/plouj/Backup/home-backup/plouj/
Jul  2 13:44:07 durandal lsyncd: Error, in Lua: default-direct.lua:146: attempt to index global 'settings' (a function value)
Jul  2 13:44:07 durandal lsyncd: Error, Backtrace 1 :default-direct.lua:146
Jul  2 13:44:07 durandal lsyncd: Error, Backtrace 2 :lsyncd.lua:1544
Jul  2 13:44:07 durandal lsyncd: Error, Backtrace 3 :lsyncd.lua:3450
</pre>

And I have only tested 1b0ac95 with default-direct.lua. Please verify that my concatenation of strings is correct.