Merge remote-tracking branch 'quintela/thread-20121220.next' into staging

* quintela/thread-20121220.next: (79 commits)
  migration: merge QEMUFileBuffered into MigrationState
  migration: fix qemu_get_fd for BufferedFile
  ram: refactor ram_save_block() return value
  ram: account the amount of transferred ram better
  ram: optimize migration bitmap walking
  ram: Use memory_region_test_and_clear_dirty
  memory: introduce memory_region_test_and_clear_dirty
  ram: Add last_sent_block
  ram: rename last_block to last_seen_block
  migration: move migration notifier
  migration: Inline qemu_fopen_ops_buffered into migrate_fd_connect
  migration: move migration_fd_put_ready()
  migration: add XFER_LIMIT_RATIO
  migration: move buffered_file.c code into migration.c
  savevm: New save live migration method: pending
  buffered_file: unfold buffered_append in buffered_put_buffer
  buffered_file: don't flush on put buffer
  buffered_file: Unfold the trick to restart generating migration data
  migration: just lock migrate_fd_put_ready
  migration: remove unfreeze logic
  ...

Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>