Make the instance volume large enough to boot from

Change-Id: If3373b5031345839ca5d0034364a18e7d329ebe3
diff --git a/nodepool/nodepool.yaml b/nodepool/nodepool.yaml
index bbe9328..c74a834 100644
--- a/nodepool/nodepool.yaml
+++ b/nodepool/nodepool.yaml
@@ -63,5 +63,6 @@
             cloud-image: pp-base-01
             flavor-name: m1.large
             boot-from-volume: True
+            volume-size: 80
     clean-floating-ips: False
     port-cleanup-interval: 0