Use nodeset legacy-ubuntu-xenial for stable branch

Change-Id: I0876d562792e3a903c3472aeb3be41d34e25d607

.zuul.yaml

@@ -1,90 +1,66 @@
 - job:
     name: heat-functional-convg-queens
     parent: heat-functional-convg-mysql-lbaasv2
+    nodeset: legacy-ubuntu-xenial
     override-checkout: stable/queens
     vars:
       branch_override: stable/queens
-    nodeset:
-      nodes:
-        - name: primary
-          label: ubuntu-xenial
 
 - job:
     name: heat-functional-orig-queens
     parent: heat-functional-orig-mysql-lbaasv2
     override-checkout: stable/queens
+    nodeset: legacy-ubuntu-xenial
     vars:
       branch_override: stable/queens
-    nodeset:
-      nodes:
-        - name: primary
-          label: ubuntu-xenial
 
 - job:
     name: heat-functional-convg-rocky
     parent: heat-functional-convg-mysql-lbaasv2
     override-checkout: stable/rocky
+    nodeset: legacy-ubuntu-xenial
     vars:
       branch_override: stable/rocky
-    nodeset:
-      nodes:
-        - name: primary
-          label: ubuntu-xenial
 
 - job:
     name: heat-functional-orig-rocky
     parent: heat-functional-orig-mysql-lbaasv2
     override-checkout: stable/rocky
+    nodeset: legacy-ubuntu-xenial
     vars:
       branch_override: stable/rocky
-    nodeset:
-      nodes:
-        - name: primary
-          label: ubuntu-xenial
 
 - job:
     name: heat-functional-convg-stein
     parent: heat-functional-convg-mysql-lbaasv2
     override-checkout: stable/stein
+    nodeset: legacy-ubuntu-xenial
     vars:
       branch_override: stable/stein
-    nodeset:
-      nodes:
-        - name: primary
-          label: ubuntu-xenial
 
 - job:
     name: heat-functional-orig-stein
     parent: heat-functional-orig-mysql-lbaasv2
     override-checkout: stable/stein
+    nodeset: legacy-ubuntu-xenial
     vars:
       branch_override: stable/stein
-    nodeset:
-      nodes:
-        - name: primary
-          label: ubuntu-xenial
 
 - job:
     name: heat-functional-convg-train
     parent: heat-functional-convg-mysql-lbaasv2
     override-checkout: stable/train
+    nodeset: legacy-ubuntu-xenial
     vars:
       branch_override: stable/train
-    nodeset:
-      nodes:
-        - name: primary
-          label: ubuntu-xenial
 
 - job:
     name: heat-functional-orig-train
     parent: heat-functional-orig-mysql-lbaasv2
     override-checkout: stable/train
+    nodeset: legacy-ubuntu-xenial
     vars:
       branch_override: stable/train
-    nodeset:
-      nodes:
-        - name: primary
-          label: ubuntu-xenial
 
 - project:
     templates: