Fix invalid #if in vnc.c when debugging is enabled (Alexander Graf)

While running with debugging enabled, I found an #if testing for
an undefined value, not defined(value). This patch fixes that.

Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>


git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@6495 c046a42c-6fe2-441c-8c8c-71466251a162
