Error notices on latest master and UPS

`Notice: Undefined variable: wpec_ash_tools in D:\wamp\www\latestwpec\wp-content\plugins\WP-e-Commerce-master\wpsc-shipping\ups_20.php on line 752`

Adding the $wpec_ash_tools to the globals seems to fix it. I looked at USPS and usps has it in the globals so i based my change on that
Merge pull request #910 from misulicus/patch-11

Error notices on latest master and UPS