Fix#2526 - List previous reviews in assignments email.
This includes a migration to update the database templates. Note that
not all templates currently included them (secdir at least), and
previous reviews are only listed in templates that included */** before.
As before, previous reviews are only included if they are done by the
same reviewer(s) as the current assignment.
This also fixes a bug in database template 182
(/group/defaults/email/open_assignments.txt) which referred to
r.review_request..doc.rev and r.review_request..requested_rev
in the template, and updates the test to use the current version of
template 182.
- Legacy-Id: 16911
Note: SVN reference [16895] has been migrated to Git commit ef1e8006f0
97be7f31ea