Stop including FileUtils.h in any header

This causes every piece of code which wants to use CFile or CDir to have to
include FileUtils.h. This causes quite some noise.

Signed-off-by: Uli Schlachter <psychon@znc.in>

modules/adminlog.cpp

@@ -6,9 +6,10 @@
  * by the Free Software Foundation.
  */
 
-#include "User.h"
 #include "Client.h"
+#include "FileUtils.h"
 #include "Server.h"
+#include "User.h"
 
 #include <syslog.h>