Fixed previous versions link to 1.8 GH repo.

Author: michael.wallis

docs/reference_earlier_versions.adoc

@@ -1,5 +1,5 @@
 ---
-sidebar: sidebar
+sidebar: docs_sidebar
 permalink: docs/reference_earlier_versions.html
 keywords: documentation, earlier, previous, versions
 summary: Documentation for previous releases of NetApp HCI is available in case you're not running the latest version.
@@ -11,6 +11,7 @@ summary: Documentation for previous releases of NetApp HCI is available in case
 :icons: font
 :linkattrs:
 :imagesdir: ../media/
+:keywords: hci, earlier, documentation, versions
 
 [.lead]
 Documentation for previous releases of NetApp HCI is available in case you're not running the latest version.