osdocs342 updates from the training repo

Author: kalexand-rh

modules/installation-initializing.adoc

@@ -39,3 +39,10 @@ link:https://godoc.org/github.com/openshift/installer/pkg/types#InstallConfig[Go
 
 . Optionally, back up the `install-config.yaml` file so that you can use
 it to install multiple clusters.
++
+[IMPORTANT]
+====
+The `install-config.yaml` file is deleted during the installation process. If
+you want to reuse the file, you must back it up now.
+====
+