Disks are client-only so we don't need to have this variable. We also
always pass false for 'isListen' to qemuBuildTLSx509BackendProps for all
disk-related code-paths so the 'tlsVerify' is ignored anyways.
Signed-off-by: NPeter Krempa <pkrempa@redhat.com>
Reviewed-by: NJán Tomko <jtomko@redhat.com>