Force screen resize if no buffer set (Avi Kivity).

This is a hack to get screen_dump to work, we should start using a global
screen_dump method.

Signed-off-by: Avi Kivity <avi@qumranet.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>


git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@4903 c046a42c-6fe2-441c-8c8c-71466251a162
