add missing awesome_nested_set 2.1.6 files (#6579)

https://github.com/collectiveidea/awesome_nested_set/commit/64cc8bc8cf93e8859a21bcf25c36675080e42ce6

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extra : convert_revision : svn%3Ae93f8b46-1217-0410-a6f0-8f06a7374b81/trunk%4013013
fix awesome_nested_set test failure (#6579)

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extra : convert_revision : svn%3Ae93f8b46-1217-0410-a6f0-8f06a7374b81/trunk%4013014