Merge remote-tracking branch 'remotes/spice/tags/pull-spice-20150529-1' into staging

spice: misc fixes.

# gpg: Signature made Fri May 29 09:16:29 2015 BST using RSA key ID D3E87138
# gpg: Good signature from "Gerd Hoffmann (work) <kraxel@redhat.com>"
# gpg:                 aka "Gerd Hoffmann <gerd@kraxel.org>"
# gpg:                 aka "Gerd Hoffmann (private) <kraxel@gmail.com>"

* remotes/spice/tags/pull-spice-20150529-1:
  spice: fix spice_chr_add_watch() pre-condition
  spice: don't update mm_time when spice-server is stopped.
  spice-char: notify the server when chardev is writable
  virtio-console: notify chardev when writable

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