This change updates our test file attachments so that they behave more

like our real file attachments. We add a with_history argument to the

TestCase.create_file_attachment method, which defaults to creating an

associated file attachment history for the file attachment. This matches the

way that file attachments are created in production. This also fixes a

discrepancy between what initial revision number is used for attachments.

In production we always set the revision to 1, but in test cases this was

being set to 0. Finally, we automatically set the draft_caption of a test

file attachment to the caption, if no draft_caption was supplied.
The number of queries for some ReviewRequestPageData.query_data_post_etag

tests were reduced because the function call no longer leads to creating

a file attachment history for the involved file attachment.
In all, these changes allow us to easily create test file attachments in

the same way that they are created in production, and makes it easier to

create new revisions for test file attachments.

Ran unit tests.
Used this in upcoming changes.