virCapabilitiesHostNUMAUnref: Accept NULL
virCapabilitiesHostNUMAUnref: Accept NULL

Fortunately, this is not causing any problems now because glib
does this check for us when calling this function via attribute
cleanup. But in a future commit we will explicitly call this
function over a struct member that might be NULL.

Signed-off-by: Michal Privoznik <83d82aaba2eed257f4814b0c239c260c4caaadf0@redhat.com>
Reviewed-by: Daniel Henrique Barboza <627b089ad62deae9aaf06ccfa2c9056df28927e0@gmail.com>

crobinso/libvirt,olafhering/libvirt,crobinso/libvirt,olafhering/libvirt,nertpinx/libvirt,fabianfreyer/libvirt,nertpinx/libvirt,zippy2/libvirt,libvirt/libvirt,nertpinx/libvirt,nertpinx/libvirt,libvirt/libvirt,olafhering/libvirt,olafhering/libvirt,jardasgit/libvirt,fabianfreyer/libvirt,jfehlig/libvirt,libvirt/libvirt,zippy2/libvirt,fabianfreyer/libvirt,jfehlig/libvirt,crobinso/libvirt,jardasgit/libvirt,jfehlig/libvirt,zippy2/libvirt,jfehlig/libvirt,nertpinx/libvirt,crobinso/libvirt,zippy2/libvirt,fabianfreyer/libvirt,jardasgit/libvirt,jardasgit/libvirt,jardasgit/libvirt,fabianfreyer/libvirt,libvirt/libvirt