Log Message:
Update ruby-kgio to 2.10.0.

=== kgio 2.10.0 - slimming down... / 2015-09-06 08:12 UTC

  The largely-unused autopush functionality is now a no-op.
  Existing applications will probably not notice, and are
  better off using MSG_MORE anyways if they're on Linux.

  Our poll(2) wrapper now uses rb_hash_clear if available,
  reducing global method cache dependence.

  shortlog of changes since 2.9.3:

        README: remove reference to Rainbows!
        writev: update comment on preserving errno
        poll: avoid rb_funcall for rb_hash_clear
        minor doc updates
        remove autopush support and make it a no-op
        HACKING: update URL for Message-ID lookup