[zserv] Extend Zserv header with version information and marker field

[zserv] Extend Zserv header with version information and marker field

2006-01-16 Paul Jakma <paul.jakma@sun.com>

	* lib/zclient.h: Update the Zserv protocol header with a version
	  field.  Define the old command field to be a 'marker', to
	  allow old Zserv and updated Zserv to be differentiated.
	  Future updates will bump the version field obviously. New
	  command field is made wider.  Try to stop using the
	  'zebra_size_t' typedef in the callbacks.
	* lib/zclient.c: Update to read/write new format header.
	* zebra/zserv.c: Ditto