[master] Added ChangeLog entry for #3913.

ChangeLog

@@ -1,3 +1,11 @@
+971.	[bug]		marcin
+	DHCPv6 server extends the lifetime of the client's lease
+	in the database when the client sends the Request message.
+	This prevents premature lease expiration before the client
+	renews the lease, according to the timers and lifetimes
+	returned by the server.
+	(Trac #3913, git 1d64829a3f1a8288dc833ed388d9ffc9fe4cf491)
+
 970.	[bug]		fdupont
 	Refactored some code to suppress cppcheck warnings.
 	(Trac #3919, git 26be6ac4cefde012ca8ef12607b6beaadca13eed)