If one of the early checks to get screen resolution fails 'screenData'
would be passed to VIR_FREE uninitialized. Unfortunately the compiler
isn't able to detect this when VIR_FREE is implemented using
g_clear_pointer.
Signed-off-by: NPeter Krempa <pkrempa@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com