Added Debian 9 support to storage test.
Added Debian 9 support to storage test.

v-sirebb/azure-linux-automation,v-sirebb/azure-linux-automation,iamshital/azure-linux-automation,iamshital/azure-linux-automation,iamshital/azure-linux-automation,konkasoftci/azure-linux-automation,konkasoftci/azure-linux-automation,konkasoftci/azure-linux-automation,v-sirebb/azure-linux-automation