Merge remote-tracking branch 'quintela/tags/migration/20170504' into staging

migration/next for 20170504

# gpg: Signature made Thu 04 May 2017 10:35:41 AM BST
# gpg:                using RSA key 0xF487EF185872D723
# gpg: Good signature from "Juan Quintela <quintela@redhat.com>"
# gpg:                 aka "Juan Quintela <quintela@trasno.org>"
# Primary key fingerprint: 1899 FF8E DEBF 58CC EE03  4B82 F487 EF18 5872 D723

* quintela/tags/migration/20170504:
  migration: Extra tracing
  migration: Move postcopy-ram.h to migration/
  monitor: Move hmp_info_snapshots from savevm.c to hmp.c
  monitor: Move hmp_delvm from savevm.c to hmp.c
  monitor: Move hmp_savevm from savevm.c to hmp.c
  monitor: Move hmp_loadvm from monitor.c to hmp.c
  monitor: Remove monitor parameter from save_vmstate
  migration: to_dst_file at that point is NULL
  migration: setup bi-directional I/O channel for exec: protocol
  ram: Split dirty bitmap by RAMBlock

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>