Properly handle the case of SetPixelEncodings with a length of zero.

This commit addresses CORE-2008-1210/CVE-2008-2382.

Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>



git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@6121 c046a42c-6fe2-441c-8c8c-71466251a162
