Merge remote-tracking branch 'remotes/amit-migration/tags/migration-for-2.6-5' into...

migration pull
 - fix a qcow2 assert
 - fix for older distros (CentOS 5)
 - documentation for vmstate flags
 - minor code rearrangement

# gpg: Signature made Fri 26 Feb 2016 15:15:15 GMT using RSA key ID 854083B6
# gpg: Good signature from "Amit Shah <amit@amitshah.net>"
# gpg:                 aka "Amit Shah <amit@kernel.org>"
# gpg:                 aka "Amit Shah <amitshah@gmx.net>"

* remotes/amit-migration/tags/migration-for-2.6-5:
  migration (postcopy): move bdrv_invalidate_cache_all of of coroutine context
  migration (ordinary): move bdrv_invalidate_cache_all of of coroutine context
  migration/vmstate: document VMStateFlags
  MAINTAINERS: Add docs/migration.txt to the "Migration" section
  migration/postcopy-ram: Guard use of sys/eventfd.h with CONFIG_EVENTFD
  migration: reorder code to make it symmetric

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