Add CHANGES entry

Add CHANGES entry

XXXX.	[func]		A default list of primary servers for the root zone is
			now built into named, allowing the "masters" statement
			to be omitted when configuring an IANA root zone
			mirror. [GL #564]

XXXX.	[func]		Attempts to use mirror zones with recursion disabled
			are now considered a configuration error. [GL #564]

XXXX.	[func]		The only valid zone-level NOTIFY settings for mirror
			zones are now "notify no;" and "notify explicit;".
			[GL #564]

XXXX.	[func]		Mirror zones are now configured using "type mirror;"
			rather than "mirror yes;". [GL #564]