Fix tools/xen/functions for bashate errors

Change I205d675ff231c0403dd135eacc8d57b45317859f modified the matching
for bashate and it has started running on this file, whereas before it
wasn't.  This fixes the errors it is now picking up.

Change-Id: I7876b5c94d90f15e3b0228999c0750bfbebcaa1c