Include 5.1.7 backport release notes

Author: fredericDelaporte

releasenotes.txt

@@ -386,6 +386,14 @@ Release notes - NHibernate - Version 5.2.0
 As part of releasing 5.2.0, a misnamed setting in 5.0.0 release notes has been fixed:
 transaction.use_connection_on_system_events correct name is transaction.use_connection_on_system_prepare
 
+Build 5.1.7
+=============================
+
+Release notes - NHibernate - Version 5.1.7
+
+** Bug
+    * #2298 Dml Linq Update Produce Wrong Sql
+
 Build 5.1.6
 =============================