Deploy RC 63 to int (again)

[stevegsa]

Why: In #2353 we changed the scrypt cost with changed the scrypt
cost which affected the session encryptor causing sessions encrypted by
old and new hosts to be incompatible. This commit hardcodes the cost in
the deprecated encryptor so that the sessions will be compatible between
hosts.

Hi! Before submitting your PR for review, and/or before merging it, please
go through the checklists below. These represent the more critical elements
of our code quality guidelines. The rest of the list can be found in
CONTRIBUTING.md

Controllers

• When adding a new controller that requires the user to be fully
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Database

• Unsafe migrations are implemented over several PRs and over several
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  will warn you about unsafe migrations and has great step-by-step instructions
  for various scenarios.

• Indexes were added if necessary. This article provides a good overview
  of indexes in Rails.

• Verified that the changes don't affect other apps (such as the dashboard)

• When relevant, a rake task is created to populate the necessary DB columns
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  who might not have interacted with this column yet (such as users who have not
  set a password yet)

• Migrations against existing tables have been tested against a copy of the
  production database. See LG-228 Make migrations safer and more resilient #2127 for an example when a migration caused deployment
  issues. In that case, all the migration did was add a new column and an index to
  the Users table, which might seem innocuous.

Encryption

• The changes are compatible with data that was encrypted with the old code.

Routes

• GET requests are not vulnerable to CSRF attacks (i.e. they don't change
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Session

• When adding user data to the session, use the user_session helper
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Testing

• Tests added for this feature/bug
• Prefer feature/integration specs over controller specs
• When adding code that reads data, write tests for nil values, empty strings,
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