* include/libvirt/libvirt.h.in, src/libvirt.c: add
        virNetworkGetBridgeName() to allow finding out what
        bridge to connect to in order to join a network.

        * src/driver.h: add networkGetBridgeName() to vtable.

        * qemud/protocol.h: add the request and reply to
        the qemud protocol.

        * qemud/dispatch.c, qemud/driver.[ch]: handle them
        here.

        * src/qemu_internal.c: implement GetBridgeName()
        in the qemu driver.

        * src/libvirt_sym.version: add new symbol.