Merge remote-tracking branch 'remotes/kraxel/tags/pull-vnc-20150216-1' into staging

vnc: fixup some QemuOpts conversion fallout.

# gpg: Signature made Mon Feb 16 08:13:32 2015 GMT 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/kraxel/tags/pull-vnc-20150216-1:
  vnc: fix coverity warning
  ui/vnc: optimize full scanline updates
  vnc: auto assian an id when calling change vnc qmp interface
  vnc: introduce an wrapper for auto assign vnc id
  vnc: using bool type instead of int for QEMU_OPT_BOOL
  vnc: correct missing property about vnc_display
  vnc: fix qemu crash when not configure vnc option

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