Following the renaming of the bridge management APIs, we can now
split the source file into 3 corresponding pieces
* src/util/virnetdev.c: APIs for any type of network interface
* src/util/virnetdevbridge.c: APIs for bridge interfaces
* src/util/virnetdevtap.c: APIs for TAP interfaces
* src/util/virnetdev.c, src/util/virnetdev.h,
src/util/virnetdevbridge.c, src/util/virnetdevbridge.h,
src/util/virnetdevtap.c, src/util/virnetdevtap.h: Copied
from bridge.{c,h}
* src/util/bridge.c, src/util/bridge.h: Split into 3 pieces
* src/lxc/lxc_driver.c, src/network/bridge_driver.c,
src/openvz/openvz_driver.c, src/qemu/qemu_command.c,
src/qemu/qemu_conf.h, src/uml/uml_conf.c, src/uml/uml_conf.h,
src/uml/uml_driver.c: Update #include directives
