s/virQEMUBuildObjectCommandlineFromJSON/virQEMUBuildObjectCommandlineFromJSONType/

The function adds the object of a certain type. Change the name so that
we make room for the generic function.
Signed-off-by: NPeter Krempa <pkrempa@redhat.com>
Reviewed-by: NJán Tomko <jtomko@redhat.com>