Ivy resolution failing with rubygems repo

[mdedetrich]

After doing a lot of debugging due to sbt/sbt#2209, I am fairly confident that there is an issue with ivy resolution for the http://rubygems-proxy.torquebox.org/releases repo

A lot of investigation has been done, using both ivyLoggingLevel := UpdateLogging.Full and logLevel in update := Level.Debug (in sbt), and it appears that ivy is just spitting out a FAILURE, without providing any reason, i.e.

[debug]         tried http://rubygems-proxy.torquebox.org/releases/rubygems/addressable/2.3.8/addressable-2.3.8.gem
[warn]  [FAILED     ] rubygems#addressable;2.3.8!addressable.gem:  (0ms)

This fork may have changed how ivy does resolution in some cases (I doubt its an issue with the mainline ivy, else a lot more people would have complained about it, and the resolution works fine with mainline maven)

For quick reference, here is a trivial build.sbt you can use to debug the issue https://gist.github.com/mdedetrich/ea95947c9b8e35a4d849