make heketi admin and user keys mandatory

Heketi has changed its default mode to authenticated and won't start if
the config file OR env does not have them set. gk-deploy should fail
early if keys are not provided than failing later.

Signed-off-by: Raghavendra Talur <rtalur@redhat.com>

deploy/gk-deploy

@@ -110,12 +110,12 @@ Options:
 
   --admin-key ADMIN_KEY
               Secret string for heketi admin user. heketi admin has access to
-              all APIs and commands. Default is to use no secret.
+              all APIs and commands. This is a required argument.
 
   --user-key USER_KEY
               Secret string for general heketi users. heketi users have access
-              to only Volume APIs. Used in dynamic provisioning. Default is to
-              use no secret.
+              to only Volume APIs. Used in dynamic provisioning. This is a
+              required argument.
 
   --daemonset-label DAEMONSET_LABEL
               Controls the value of the label set on nodes which will host pods
@@ -598,6 +598,11 @@ END
   fi
 fi
 
+if [[ "x${ADMIN_KEY}" == "x" || "x${USER_KEY}" == "x"  ]]; then
+  output "heketi admin and user keys are required!"
+  exit 1
+fi
+
 if [[ "x${CLI}" == "x" ]]; then
   kubectl=$(type kubectl 2>/dev/null | awk '{print $3}')
   oc=$(type oc 2>/dev/null | awk '{print $3}')