Fix nodepool label name

Change-Id: Ida90f41695ef220b774a8fc6b72cd611eacc8b71
diff --git a/zuul.d/charm-cinder-storpool-iscsi.yaml b/zuul.d/charm-cinder-storpool-iscsi.yaml
index 95a4bb2..f6dfaf2 100644
--- a/zuul.d/charm-cinder-storpool-iscsi.yaml
+++ b/zuul.d/charm-cinder-storpool-iscsi.yaml
@@ -126,7 +126,7 @@
     nodeset:
       nodes:
         - name: controller
-          label: os-ubuntu-focal
+          label: charm-main-os-ubuntu-focal
     secrets:
       - name: CHARMCRAFT_AUTH
         secret: CHARMCRAFT_AUTH