VOL-1468 : Ensure hash is kept and latest is set

Change-Id: I6ea53b7da41963c9ecce4df2c6d9a320c79930fc
diff --git a/db/model/persisted_revision.go b/db/model/persisted_revision.go
index 39bef5e..fa35eca 100644
--- a/db/model/persisted_revision.go
+++ b/db/model/persisted_revision.go
@@ -141,9 +141,11 @@
 						rev := branch.GetLatest()
 						updatedRev := rev.UpdateData(data.Interface(), branch)
 
-						// The changeAnnouncement field should remain 'nil' to prevent
-						// update callbacks from being executed.
-						rev.GetNode().makeLatest(branch, updatedRev, nil)
+						// ensure that we keep the previous hash value
+						updatedRev.SetHash(rev.GetHash())
+
+						// Save revision
+						branch.SetLatest(updatedRev)
 					}
 				}