fence_azure_arm: use skip_shutdown feature when available

The "skip_shutdown" parameter is ignored in older Azure SDK, so there's
no need for a fallback option.

agents/azure_arm/fence_azure_arm.py

@@ -114,8 +114,8 @@ def set_power_status(clients, options):
                 azure_fence.set_network_state(compute_client, network_client, rgName, vmName, "unblock")
 
         if (options["--action"]=="off"):
-            logging.info("Deallocating " + vmName + " in resource group " + rgName)
-            compute_client.virtual_machines.deallocate(rgName, vmName)
+            logging.info("Poweroff " + vmName + " in resource group " + rgName)
+            compute_client.virtual_machines.power_off(rgName, vmName, skip_shutdown=True)
         elif (options["--action"]=="on"):
             logging.info("Starting " + vmName + " in resource group " + rgName)
             compute_client.virtual_machines.start(rgName, vmName)
@@ -199,7 +199,7 @@ def main():
 
     docs = {}
     docs["shortdesc"] = "Fence agent for Azure Resource Manager"
-    docs["longdesc"] = "Used to deallocate virtual machines and to report power state of virtual machines running in Azure. It uses Azure SDK for Python to connect to Azure.\
+    docs["longdesc"] = "fence_azure_arm is an I/O Fencing agent for Azure Resource Manager. It uses Azure SDK for Python to connect to Azure.\
 \n.P\n\
 For instructions to setup credentials see: https://docs.microsoft.com/en-us/azure/azure-resource-manager/resource-group-create-service-principal-portal\
 \n.P\n\

tests/data/metadata/fence_azure_arm.xml

@@ -1,6 +1,6 @@
 <?xml version="1.0" ?>
 <resource-agent name="fence_azure_arm" shortdesc="Fence agent for Azure Resource Manager" >
-<longdesc>Used to deallocate virtual machines and to report power state of virtual machines running in Azure. It uses Azure SDK for Python to connect to Azure.
+<longdesc>fence_azure_arm is an I/O Fencing agent for Azure Resource Manager. It uses Azure SDK for Python to connect to Azure.
 
 For instructions to setup credentials see: https://docs.microsoft.com/en-us/azure/azure-resource-manager/resource-group-create-service-principal-portal