Commit 72862797 introduced resolution settings for QEMU video drivers.
It includes a new structure inside video definition. So, the code needs
to clear pointer allocation for that structure into clear function
virDomainVideoDefClear(). This commit adds this missing VIR_FREE().
Reviewed-by: NJonathon Jongsma <jjongsma@redhat.com>
Signed-off-by: NJulio Faracco <jcfaracco@gmail.com>