Fix STC scripts for checking ONOS nodes

- Fix onos-check-nodes to return an error code if  onos is up but nodes
  aren't in the correct states
- Add onos-check-storage-nodes to check if all atomix core nodes are
  connected
- Add a step for onos-check-storage-nodes step to stc setup

Change-Id: If61c2316653b6dc359fc84f18a65b2edbdd4acd8
diff --git a/tools/test/scenarios/setup.xml b/tools/test/scenarios/setup.xml
index 10073e0..a830100 100644
--- a/tools/test/scenarios/setup.xml
+++ b/tools/test/scenarios/setup.xml
@@ -110,6 +110,8 @@
 
                 <step name="Check-Nodes-${#}" exec="onos-check-nodes ${OC#}" delay="3"
                       requires="~Wait-for-Start-${#}"/>
+                <step name="Check-Storage-Nodes-${#}" exec="onos-check-storage-nodes ${OC#}" delay="3"
+                      requires="~Wait-for-Start-${#}"/>
                 <step name="Check-Components-${#}" delay="5"
                       exec="onos-check-components ${OC#}"
                       requires="~Wait-for-Start-${#}"/>