[#3498249] Support sqlite schema (again).

cas_server.install

@@ -22,6 +22,7 @@ function cas_server_schema() {
       ],
       'expiration' => [
         'description' => 'Time after which the ticket is invalid.',
+        'type' => 'int',
         'mysql_type' => 'datetime',
         'pgsql_type' => 'timestamp',
         'not null' => TRUE,