Fix monitor command (screendump) (Stefan Weil)

starting with r6839, the monitor command 'screendump'
raises a nullpointer memory access which crashs Qemu.

Fix crash when calling screendump from monitor.

This was a regression introduced with r6839:
DisplayAllocator interface (Stefano Stabellini)

Signed-off-by: Stefan Weil <weil@mail.berlios.de>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>


git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@6900 c046a42c-6fe2-441c-8c8c-71466251a162
diff --git a/hw/vga.c b/hw/vga.c
index eeb77f1..b1e4373 100644
--- a/hw/vga.c
+++ b/hw/vga.c
@@ -2637,6 +2637,7 @@
     dcl.dpy_resize = vga_save_dpy_resize;
     dcl.dpy_refresh = vga_save_dpy_refresh;
     register_displaychangelistener(ds, &dcl);
+    ds->allocator = &default_allocator;
     ds->surface = qemu_create_displaysurface(ds, w, h);
 
     s->ds = ds;