OO-2621 update info msg on db

src/main/java/org/olat/commons/info/manager/InfoMessageFrontendManagerImpl.java

@@ -176,6 +176,7 @@ public class InfoMessageFrontendManagerImpl implements InfoMessageFrontendManage
 			if (modifier != null && modifier.equals(identity)) {
 				infoMessage.setModifier(null);
 			}
+			infoMessageManager.saveInfoMessage(infoMessage);
 		}		
 	}