added xmlname to DomainGraphic to marshal correctly
added xmlname to DomainGraphic to marshal correctly

The <graphics> element can also be used as a document root
when dynamically updating graphics config in libvirt.

Signed-off-by: Daniel Kucera <06f3fcaeda0d958d13b26c781f476ff8ca65ba9d@apptocloud.com>

libvirt/libvirt-go-xml