Merge "Check whether $CFG->cacheversion exists before initializing it" into 1.9_STABLE

htdocs/lib/db/upgrade.php

@@ -3217,7 +3217,9 @@ function xmldb_core_upgrade($oldversion=0) {
         // to tell cacheing software when they've been updated. (Without having to use the Mahara
         // minor version for that purpose.)
         // Set this to a random starting number to make minor version slightly harder to detect
+        if (!get_config('cacheversion')) {
             set_config('cacheversion', rand(1000, 9999));
         }
+    }
     return $status;
 }