Remove fedora nodeset

It turns out, that the fedora 3node nodeset is not used since
change Ic3493edae66df736ff29e3c3e82774e2649cef9d merged.

Remove it, so that we don't need to update it again in the future.

Change-Id: Ib65affbe84937e2e0bc0a3bec7fb9c21cfeb3636

zuul.d/nodes.yaml

@@ -1,38 +1,3 @@
-- nodeset:
-     name: openstack-three-node-fedora-latest
-     nodes:
-       - name: controller
-         label: fedora-30
-       - name: compute1
-         label: fedora-30
-       - name: compute2
-         label: fedora-30
-     groups:
-       # Node where tests are executed and test results collected
-       - name: tempest
-         nodes:
-           - controller
-       # Nodes running the compute service
-       - name: compute
-         nodes:
-           - compute1
-           - compute2
-       # Nodes that are not the controller
-       - name: subnode
-         nodes:
-           - compute1
-           - compute2
-       # Switch node for multinode networking setup
-       - name: switch
-         nodes:
-           - controller
-       # Peer nodes for multinode networking setup
-       - name: peers
-         nodes:
-           - compute1
-           - compute2
-
-
 - nodeset:
      name: openstack-three-node-centos-7
      nodes: