Fix VM_EXTRADISKS_LIST default

Currently this is wrong, since the primary disk shows up as sda
due to using virtio-scsi, but then the single additional disk
uses virtio and shows up as vda, not vdb.

common.sh

@@ -247,7 +247,7 @@ export NUM_WORKERS=${NUM_WORKERS:-"2"}
 export NUM_EXTRA_WORKERS=${NUM_EXTRA_WORKERS:-"0"}
 export EXTRA_WORKERS_ONLINE_STATUS=${EXTRA_WORKERS_ONLINE_STATUS:-"true"}
 export VM_EXTRADISKS=${VM_EXTRADISKS:-"false"}
-export VM_EXTRADISKS_LIST=${VM_EXTRADISKS_LIST:-"vdb"}
+export VM_EXTRADISKS_LIST=${VM_EXTRADISKS_LIST:-"vda"}
 export VM_EXTRADISKS_SIZE=${VM_EXTRADISKS_SIZE:-"8G"}
 export MASTER_HOSTNAME_FORMAT=${MASTER_HOSTNAME_FORMAT:-"master-%d"}
 export WORKER_HOSTNAME_FORMAT=${WORKER_HOSTNAME_FORMAT:-"worker-%d"}

vm_setup_vars.yml

@@ -10,7 +10,7 @@ ironic_prefix: "{{ ironic_prefix }}"
 num_masters: 3
 num_workers: 1
 num_extraworkers: 0
-extradisks_list: "{{ lookup('env', 'VM_EXTRADISKS_LIST').split(' ') | default(['vdb']) }}"
+extradisks_list: "{{ lookup('env', 'VM_EXTRADISKS_LIST').split(' ') | default(['vda']) }}"
 extradisks_size: "{{ lookup('env', 'VM_EXTRADISKS_SIZE') | default(['8G']) }}"
 flavors:
   master: