Make `rbx report` work again with GitHub API v3.

With our latest release its more likely that rubinius will get
more users trying it. When something goes wrong we instruct people
to submit a crash report using the `rbx report` tool, this was
however broken as it needed to be updated for working with latest
github api v3.



I was lurking on the irc channel and saw @brixen mention to
@jnimety this was not working, so I just went on fixing this.