* include/libvirt/libvirt.h.in: add VIR_UUID_BUFLEN and
        VIR_UUID_STRING_BUFLEN

        * libvirt/proxy/libvirt_proxy.c, libvirt/src/hash.c,
        libvirt/src/internal.h, libvirt/src/libvirt.c,
        libvirt/src/proxy_internal.c, libvirt/src/test.c,
        libvirt/src/virsh.c, libvirt/src/xend_internal.c,
        libvirt/src/xm_internal.c, libvirt/src/xml.c,
        libvirt/python/libvir.c: use them