Migration bits from the COLO project

# gpg: Signature made Sun 30 Oct 2016 10:39:55 GMT
# gpg:                using RSA key 0xEB0B4DFC657EF670
# gpg: Good signature from "Amit Shah <amit@amitshah.net>"
# gpg:                 aka "Amit Shah <amit@kernel.org>"
# gpg:                 aka "Amit Shah <amitshah@gmx.net>"
# Primary key fingerprint: 48CA 3722 5FE7 F4A8 B337  2735 1E9A 3B5F 8540 83B6
#      Subkey fingerprint: CC63 D332 AB8F 4617 4529  6534 EB0B 4DFC 657E F670

* remotes/amit-migration/tags/migration-for-2.8:
  MAINTAINERS: Add maintainer for COLO framework related files
  configure: Support enable/disable COLO feature
  docs: Add documentation for COLO feature
  COLO: Implement failover work for secondary VM
  COLO: Implement the process of failover for primary VM
  COLO: Introduce state to record failover process
  COLO: Add 'x-colo-lost-heartbeat' command to trigger failover
  COLO: Synchronize PVM's state to SVM periodically
  COLO: Add checkpoint-delay parameter for migrate-set-parameters
  COLO: Load VMState into QIOChannelBuffer before restore it
  COLO: Send PVM state to secondary side when do checkpoint
  COLO: Add a new RunState RUN_STATE_COLO
  COLO: Introduce checkpointing protocol
  COLO: Establish a new communicating path for COLO
  migration: Switch to COLO process after finishing loadvm
  migration: Enter into COLO mode after migration if COLO is enabled
  COLO: migrate COLO related info to secondary node
  migration: Introduce capability 'x-colo' to migration
Signed-off-by: NPeter Maydell <peter.maydell@linaro.org>