Updated runtime files.  Remove version checks for Vim older than 6.0.
diff --git a/runtime/syntax/aptconf.vim b/runtime/syntax/aptconf.vim
index 7a31b2d..8cb1432 100644
--- a/runtime/syntax/aptconf.vim
+++ b/runtime/syntax/aptconf.vim
@@ -3,12 +3,9 @@
 " Maintainer:	Yann Amar <quidame@poivron.org>
 " Last Change:	2015 Dec 22
 
-" For version 5.x: Clear all syntax items
-" For version 6.x and 7.x: Quit when a syntax file was already loaded
+" quit when a syntax file was already loaded
 if !exists("main_syntax")
-  if version < 600
-    syntax clear
-  elseif exists("b:current_syntax")
+  if exists("b:current_syntax")
     finish
   endif
   let main_syntax = 'aptconf'