[zebra] Fix forgetfulness wrt configured address on FreeBSD

[zebra] Fix forgetfulness wrt configured address on FreeBSD

2006-06-15 Paul Jakma <paul.jakma@sun.com>

	* (general) The key fixes are actually Andrew Schorr's.
	* interface.c: (ip_address_uninstall) Unset the configured flag.
	* connected.c: (connected_same) new helper, check whether
	  two connected are same.
	  (connected_implicit_withdraw) new helper, consolidation of
	  existing code in connected_add_ipv{4,6}.
	  Try filter out unneeded Zserv address delete/adds when
	  address is exact same.
	  Where old address is implicitely removed, be sure to preserve
	  the IFC_CONFIGURED flag if set, fixes bug where configured
	  addresses were being lost on FreeBSD.