don't use a negative value for PROVISION_SUCESS

Just a small nitpick, but I'm worried about the effect of a negative value in the PROVISION_* error bitmasks. It should probably be just zero instead of -1. Adrian was saying that the error value wasn't actually checked for signed anywhere and this was probably fine.

Here is the trivial patch:

--- provision_errors.inc	19 Jan 2008 08:02:20 -0000	1.2
+++ provision_errors.inc	7 Mar 2008 20:21:51 -0000
@@ -13,7 +13,7 @@
 */
 
 /** Succesful **/
-define('PROVISION_SUCCESS', -1);
+define('PROVISION_SUCCESS', 0);
 /** Database could not be accessed, or configured */
 define('PROVISION_DB_ERROR', 1);
 /** Drupal was unable to complete it's installation */

I'm filing this here instead of committing it because we don't want to introduce a bug with this (mostly cosmetic) fix until we actually get a release out there...