Merge remote-tracking branch 'remotes/juanquintela/tags/pull-migration-pull-request' into staging

Migration pull request

# gpg: Signature made Thu 13 Feb 2020 13:04:43 GMT
# gpg:                using RSA key 1899FF8EDEBF58CCEE034B82F487EF185872D723
# gpg: Good signature from "Juan Quintela <quintela@redhat.com>" [full]
# gpg:                 aka "Juan Quintela <quintela@trasno.org>" [full]
# Primary key fingerprint: 1899 FF8E DEBF 58CC EE03  4B82 F487 EF18 5872 D723

* remotes/juanquintela/tags/pull-migration-pull-request:
  git: Make submodule check only needed modules
  migration-test: fix some memleaks in migration-test
  tests/migration: Add some slack to auto converge
  migration/rdma: rdma_accept_incoming_migration fix error handling
  migration: Optimization about wait-unplug migration state
  migration: Maybe VM is paused when migration is cancelled

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