Merge remote-tracking branch 'remotes/dgilbert/tags/pull-migration-20181031a' into...

Minor migration fixes 2018-10-31

# gpg: Signature made Wed 31 Oct 2018 16:55:40 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-20181031a:
  migration: avoid segmentfault when take a snapshot of a VM which being migrated
  qapi: Fix COLOStatus and query-colo-status since version
  COLO: Fix Colo doc secondeary should be secondary

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