Changing test to not use Order object

[daveerickson]

I also ran into the issue identified in #505 within my project since my org does not have Orders enabled.

I changed Order object to List Email since that seems to be one of few that do not need to be enabled and has Activities enabled. I am open to refactoring to a different object if List Email is not preferred.

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This change is 

[daveespo]

Thanks -- finding a set of standard object that's available regardless of flavor/generation/type of org is like walking a mine field. I have no affinity to the Order object so we can give ListEmails a try instead.

Reviewed 1 of 1 files at r1, all commit messages.
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[daveerickson]

Yeah, I was walking describe info for Opportunity to find List Email. :)

Thanks for being flexible, and for the quick response.