spice: call qemu_spice_set_passwd() during init

Don't call SPICE API directly to set password given in command line, but
use the internal API, saving password for later calls.

This solves losing password when changing expiration in qemu monitor.

https://bugzilla.redhat.com/show_bug.cgi?id=1138639

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Merge remote-tracking branch 'remotes/spice/tags/pull-spice-20140916-2' into staging

spice: call qemu_spice_set_passwd() during init

# gpg: Signature made Tue 16 Sep 2014 07:11:22 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-20140916-2:
  spice: call qemu_spice_set_passwd() during init

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