Fix missing labels

I forgot to add the top-level label entries for the new node types.

Set them all to min-ready: 0 while we decide which to use.

Change-Id: Ifa08b1e2dc3a08391b55b2216f93051020e9ac6a
diff --git a/nodepool/nodepool.yaml b/nodepool/nodepool.yaml
index 9543d3f..b45e059 100644
--- a/nodepool/nodepool.yaml
+++ b/nodepool/nodepool.yaml
@@ -33,4 +33,8 @@
             volume-size: 40
 labels:
   - name: debian-stretch-8G
-    min-ready: 1
+    min-ready: 0
+  - name: debian-stretch-30G
+    min-ready: 0
+  - name: debian-stretch-60G
+    min-ready: 0