issue #1309 keep themes_installed compatible with an old PHP5

admin/themes_installed.php

@@ -146,7 +146,7 @@ function cmp($a, $b)
   if($a['STATE'] == $b['STATE'])
     return strcasecmp($a['NAME'], $b['NAME']); 
   else
-    return $s[$a['STATE']] <=> $s[$b['STATE']]; 
+    return ($s[$a['STATE']] >= $s[$b['STATE']] ? 1 : 0);
 }
 usort($tpl_themes, 'cmp');