[3150] ChangeLog updated.

ChangeLog

-672.	[func]	tmark
+6XX.	[func]		tomek
+	libdhcpsrv: CfgMgr is now able to store IA, TA and PD pools in
+	Subnet6 structures.
+	(Trac #3150, git ABCD)
+
+672.	[func]		tmark
 	Added b10-dhcp-ddnsupdate transaction base class, NameChangeTransaction.
-	This class provides the common structure and methods to implement the state 
-	models described in the DHCP_DDNS design, plus integration with DNSClient 
+	This class provides the common structure and methods to implement the state
+	models described in the DHCP_DDNS design, plus integration with DNSClient
 	and its callback mechanism for asynchronous IO with the DNS servers.
 	(Trac #3086, git 079b862c9eb21056fdf957e560b8fe7b218441b6)