Satisfy version checker requirements

In stable branches, 8 first digits of the backup version
must be >= than the 8 first digits of the main version.

backup/backup.class.php

@@ -109,7 +109,7 @@ abstract class backup implements checksumable {
     const OPERATION_RESTORE ='restore';// We are performing one restore
 
     // Version (to keep CFG->backup_version (and release) updated automatically)
-    const VERSION = 2012061800;
+    const VERSION = 2012062500;
     const RELEASE = '2.3';
 }