Merge remote-tracking branch 'remotes/dgilbert/tags/pull-migration-20190405a' into...

Merge remote-tracking branch 'remotes/dgilbert/tags/pull-migration-20190405a' into staging

Migration fixes pull for 4.0

A couple of fixes for crashes in colo and
migration parameters.

# gpg: Signature made Fri 05 Apr 2019 16:47:38 BST
# gpg:                using RSA key 45F5C71B4A0CB7FB977A9FA90516331EBC5BFDE7
# gpg: Good signature from "Dr. David Alan Gilbert (RH2) <dgilbert@redhat.com>" [full]
# Primary key fingerprint: 45F5 C71B 4A0C B7FB 977A  9FA9 0516 331E BC5B FDE7

* remotes/dgilbert/tags/pull-migration-20190405a:
  migration: Fix migrate_set_parameter
  migration/ram.c: Fix codes conflict about bitmap_mutex

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