.zuul: Use less cryptic names for the nodes

The name of a node in a nodeset is meant to be a human-readable name.  A
name with an obscure prefix like 'ci-node-' makes it look more profound
than it really is.

https://github.com/containers/toolbox/pull/1206

.zuul.yaml

@@ -43,7 +43,7 @@
     timeout: 3600
     nodeset:
       nodes:
-        - name: ci-node-rawhide
+        - name: fedora-rawhide
           label: cloud-fedora-rawhide
     pre-run: playbooks/setup-env.yaml
     run: playbooks/system-test.yaml
@@ -54,7 +54,7 @@
     timeout: 1200
     nodeset:
       nodes:
-        - name: ci-node-36
+        - name: fedora-36
           label: cloud-fedora-36
     pre-run: playbooks/setup-env.yaml
     run: playbooks/system-test.yaml
@@ -65,7 +65,7 @@
     timeout: 1200
     nodeset:
       nodes:
-        - name: ci-node-35
+        - name: fedora-35
           label: cloud-fedora-35
     pre-run: playbooks/setup-env.yaml
     run: playbooks/system-test.yaml