Merge remote-tracking branch 'remotes/mjt/tags/pull-trivial-patches-2015-05-09' into staging

trivial patches for 2015-05-09

# gpg: Signature made Fri May  8 22:58:42 2015 BST using RSA key ID A4C3D7DB
# gpg: Good signature from "Michael Tokarev <mjt@tls.msk.ru>"
# gpg:                 aka "Michael Tokarev <mjt@corpit.ru>"
# gpg:                 aka "Michael Tokarev <mjt@debian.org>"

* remotes/mjt/tags/pull-trivial-patches-2015-05-09:
  docs: update BLOCK_IMAGE_CORRUPTED documentation
  glib-compat.h: change assert to g_assert
  Remove various unused functions
  sheepdog: fix resource leak with sd_snapshot_create
  xhci: remove unused code

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