Remove redundunt instance_configured

If the instance is a cluster, then it will be configured and the earlier
check for /etc/github/configured will have set instance_configured to
true.

Author: snh

bin/ghe-restore

@@ -93,7 +93,6 @@ cluster=false
 if ghe-ssh "$GHE_HOSTNAME" -- \
   "[ -f '$GHE_REMOTE_ROOT_DIR/etc/github/cluster' ]"; then
   cluster=true
-  instance_configured=true
 fi
 
 # Restoring a cluster backup to a standalone appliance is not supported