Merge remote-tracking branch 'remotes/dgilbert/tags/pull-migration-20180615a' into staging

Migration pull 2018-06-15

# gpg: Signature made Fri 15 Jun 2018 16:13:17 BST
# gpg:                using RSA key 0516331EBC5BFDE7
# gpg: Good signature from "Dr. David Alan Gilbert (RH2) <dgilbert@redhat.com>"
# Primary key fingerprint: 45F5 C71B 4A0C B7FB 977A  9FA9 0516 331E BC5B FDE7

* remotes/dgilbert/tags/pull-migration-20180615a:
  migration: calculate expected_downtime with ram_bytes_remaining()
  migration/postcopy: Wake rate limit sleep on postcopy request
  migration: Wake rate limiting for urgent requests
  migration/postcopy: Add max-postcopy-bandwidth parameter
  migration: introduce migration_update_rates
  migration: fix counting xbzrle cache_miss_rate
  migration/block-dirty-bitmap: fix dirty_bitmap_load
  migration: Poison ramblock loops in migration
  migration: Fixes for non-migratable RAMBlocks
  typedefs: add QJSON

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