Backported #7072 to 3-2-stable. Use database value for uniqueness validation scope.
Merge pull request #9430 from authorNari/backport-7072-to-3-2-stable

Backported #7072 to 3-2-stable. Use database value for uniqueness validation scope
Improve changelog entry [ci skip]
Do not override attributes on `dup` by default scopes
Revert "Merge pull request #9208 from dylanahsmith/3-2-mysql-quote-numeric"

This reverts commit 921a296a3390192a71abeec6d9a035cc6d1865c8.
CHANGELOG entry for ee291b9.

Since we released it, it should go in the CHANGELOG.
Tighten up AS.gemspec.

Apparently 0.6.2 has a call to force_encoding, which is not around
in 1.8.7.