OCPBUGS#10516: Fix the zone group

Author: xenolinux

modules/installation-localzone-generate-k8s-manifest.adoc

@@ -155,7 +155,7 @@ spec:
       metadata:
         labels:
           zone_type: local-zone
-          zone_group: ${LZ_ZONE_NAME::-1}
+          zone_group: ${LZ_ZONE_NAME:0:-1}
           node-role.kubernetes.io/edge: ""
       taints:
         - key: node-role.kubernetes.io/edge