Merge remote-tracking branch 'remotes/amit-migration/tags/migration-for-2.7-7' into staging

Migration:
 - couple of bug fixes
 - couple of typo fixes

# gpg: Signature made Thu 11 Aug 2016 12:36:00 BST
# gpg:                using RSA key 0xEB0B4DFC657EF670
# gpg: Good signature from "Amit Shah <amit@amitshah.net>"
# gpg:                 aka "Amit Shah <amit@kernel.org>"
# gpg:                 aka "Amit Shah <amitshah@gmx.net>"
# Primary key fingerprint: 48CA 3722 5FE7 F4A8 B337  2735 1E9A 3B5F 8540 83B6
#      Subkey fingerprint: CC63 D332 AB8F 4617 4529  6534 EB0B 4DFC 657E F670

* remotes/amit-migration/tags/migration-for-2.7-7:
  migration/socket: fix typo in file header
  migration: fix live migration failure with compression
  migration: mmap error check fix
  migration/ram: fix typo

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