Merge remote-tracking branch 'remotes/dgilbert/tags/pull-migration-20181121a' into...

Merge remote-tracking branch 'remotes/dgilbert/tags/pull-migration-20181121a' into staging

Migration fixes 2018-11-21

Notably the fix for building with --disable-replication

# gpg: Signature made Wed 21 Nov 2018 13:03:20 GMT
# 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-20181121a:
  migration/migration.c: Add COLO dependency checks
  migration/colo.c: Fix compilation issue when disable replication

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