notify.php gives error if nothing to notify - bug in underlying db functions

[Nicolas]

yoyo reported getting this in the log of a new project, with no user subscribed to get delayed forum/PM notifications:

PHP Notice:  Undefined variable: x in /home/boincadm/projects/rnaworld/html/inc/db_conn.inc on line 90
PHP Warning:  Invalid argument supplied for foreach() in /home/boincadm/projects/rnaworld/html/ops/notify.php on line 69

The problem is that if a query in enum_general returns 0 rows, the local variable $x inside that function is never set at all, so it returns NULL. The following patch makes it return an empty array instead:

html/inc/db_conn.inc

@@ -83 +83 @@
     function enum_general($classname, $query) {
         $result = $this->do_query($query);
         if (!$result) return null;
+        $x = array();
         while ($obj = mysql_fetch_object($result, $classname)) {
             $x[] = $obj;
         }

[davea]

(In [20178]) - web DB code: fix PHP warning when enumeration returns nothing.

From Nicolas. fixes #974

• client: tiny code shuffle