luahttp: Actually load the base directory

Fix regression introduced in 6a7c3718 where luahttp does not load the base directory, causing 404s
Signed-off-by: Jean-Baptiste Kempf <jb@videolan.org>

share/lua/intf/http.lua

@@ -320,4 +320,5 @@ end
 
 password = vlc.var.inherit(nil,"http-password")
 h = vlc.httpd()
+load_dir( http_dir )
 local a = h:handler("/art",nil,password,callback_art,nil)