Update notes for submitted changes

* Return a new instance from openSystemConfig and openUserConfig

af/0296b42c150cf2191e2279cb50cfec8ff8a270

@@ -0,0 +1,7 @@
+Code-Review+2: Jonathan Nieder <jrn@google.com>
+Verified+1: JGit Bot <jgit-bot@eclipse.org>
+Submitted-by: Jonathan Nieder <jrn@google.com>
+Submitted-at: Thu, 29 Aug 2019 21:11:33 -0400
+Reviewed-on: https://git.eclipse.org/r/148373
+Project: jgit/jgit
+Branch: refs/heads/stable-5.1