Merge remote-tracking branch 'remotes/juanquintela/tags/migration/20150930' into staging

migration/next for 20150930

# gpg: Signature made Wed 30 Sep 2015 09:24:02 BST using RSA key ID 5872D723
# gpg: Good signature from "Juan Quintela <quintela@redhat.com>"
# gpg:                 aka "Juan Quintela <quintela@trasno.org>"

* remotes/juanquintela/tags/migration/20150930:
  migration: Disambiguate MAX_THROTTLE
  qmp/hmp: Add throttle ratio to query-migrate and info migrate
  migration: Dynamic cpu throttling for auto-converge
  migration: Parameters for auto-converge cpu throttling
  cpu: Provide vcpu throttling interface
  migration: yet more possible state transitions

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>