Introduce fuzzy logic for email checking to make tests less brittle

The email text has changed twice, and I don't think we need to be very specific with what we check, so I made this change to hopefully make the tests less prone to breakage when they tweak the email text.

This addresses 3 failures as seen at http://qa-selenium.mv.mozilla.com:8080/view/BIDPOM/job/bidpom.stage/335/testReport/