[DRE-maint] ruby-devise-async is marked for autoremoval from testing

[Debian testing autoremoval watch]

ruby-devise-async 0.9.0-1 is marked for autoremoval from testing on 2016-08-25

It (build-)depends on packages with these RC bugs:
830917: ruby-omniauth-openid: Gem::LoadError: Could not find 'rack-openid' (~> 1.3.1) - did find: [rack-openid-1.4.2]