python: fix Spice.Audio binding

The spice_audio_new() function is not correctly generated h2def.py
anymore because of the surrounding #ifdef and macros. Add it in
the manual.defs instead.

Avoid API breakage:
2012-05-10 01:56:48,884 (cli:83): Uncaught exception:
Traceback (most recent call last):
  File /usr/share/virt-manager/virtManager/console.py, line 475, in
_channel_new_cb
    self.audio = spice.Audio(self.spice_session)
TypeError: GObject.__init__() takes exactly 0 arguments (1 given)

https://bugzilla.redhat.com/show_bug.cgi?id=820335

gtk/spice-client-gtk-manual.defs

@@ -104,3 +104,14 @@
     '("failed" "SPICE_CLIENT_ERROR_FAILED")
   )
 )
+
+(define-function spice_audio_new
+  (c-name "spice_audio_new")
+  (is-constructor-of "SpiceAudio")
+  (return-type "SpiceAudio*")
+  (parameters
+    '("SpiceSession*" "session")
+    '("GMainContext*" "context")
+    '("const-char*" "name")
+  )
+)