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

Migration pull request

# gpg: Signature made Fri 28 Feb 2020 09:21:31 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:
  savevm: Don't call colo_init_ram_cache twice
  migration/colo: wrap incoming checkpoint process into new helper
  migration: fix COLO broken caused by a previous commit
  migration/block: rename BLOCK_SIZE macro
  migration/savevm: release gslist after dump_vmstate_json
  test-vmstate: Fix memleaks in test_load_qlist
  migration/vmstate: Remove redundant statement in vmstate_save_state_v()
  multifd: Add zstd compression multifd support
  multifd: Add multifd-zstd-level parameter
  configure: Enable test and libs for zstd
  multifd: Add zlib compression multifd support
  multifd: Add multifd-zlib-level parameter
  multifd: Make no compression operations into its own structure
  migration: Add support for modules
  multifd: Add multifd-compression parameter

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