max date on the audit log fix up

fixes: CNVS-16213

Sets a max date on the audit log data fixup so it does not have to run
records that were created after the bug was fixed.  Set it to the 20th
of August to give us a buffer and that was when the audit logs were
reenabled.

Test Plan:

  - Create a corrupted login event using the script below.
  - Run the fixup (Command in script below).
  - Should skip records after the 20th (see output from script ids to which 
    is which).

Setup test plan:

target_user = User.find(...)
target_pseudonym = target_user.pseudonyms.first
event_type = 'login'

# Records Before
record1 = Auditors::Authentication::Record.generate(target_pseudonym,  event_type)
record1.attributes['created_at'] = Date.new(2014, 8, 20).to_time
Auditors::Authentication::Stream.insert(record1)

record2 = Auditors::Authentication::Record.generate(target_pseudonym, event_type)
record2.attributes['id'] = record1.id
record2.attributes['created_at'] = Date.new(2014, 8, 21).to_time
Auditors::Authentication::Stream.insert(record2)

# Records After
record3= Auditors::Authentication::Record.generate(target_pseudonym,  event_type)
record3.attributes['created_at'] = Date.new(2014, 8, 21).to_time
Auditors::Authentication::Stream.insert(record3)

record4 = Auditors::Authentication::Record.generate(target_pseudonym,  event_type)
record4.attributes['id'] = record3.id
record4.attributes['created_at'] = Date.new(2014, 8, 22).to_time
Auditors::Authentication::Stream.insert(record4)

puts "Id should be fixed: #{record1.id}."
puts "Id should NOT be fixed: #{record3.id}."


# Run Fixup
DataFixup::FixAuditLogUuidIndexes::Migration::run

Change-Id: Ic57fe4da0ecedba9f45670dca08e5b279b601086
Reviewed-on: https://gerrit.instructure.com/42605
Reviewed-by: Jacob Fugal <jacob@instructure.com>
QA-Review: Jeremy Putnam <jeremyp@instructure.com>
Tested-by: Jenkins <jenkins@instructure.com>
Product-Review: Nick Cloward <ncloward@instructure.com>