0.8dev: When at global scope, use the `[ticket] default product` as the default value. Refs #304.

Before this change, the product select would be set to the empty value and the //Create// button would be disabled until a product is selected. That behavior is preserved when `[ticket] default product` has not been set.


git-svn-id: https://svn.apache.org/repos/asf/bloodhound/trunk@1553998 13f79535-47bb-0310-9956-ffa450edef68