Fix nodepool-zuul-functional

Several fixes to this job:

Use pip3 in the setup script as nodepool is v3 only; this whole script
needs to be made native, but this works for now.

Make sure we pass a list as the Node() request name

Update accpetNodes call to pass id

Change-Id: I3d064e6c1df02f1dad2a08855927703a0e23a047
diff --git a/tools/nodepool-integration-setup.sh b/tools/nodepool-integration-setup.sh
index 58c39cf..67d766d 100755
--- a/tools/nodepool-integration-setup.sh
+++ b/tools/nodepool-integration-setup.sh
@@ -7,6 +7,6 @@
 
 cd /tmp/openstack-infra/nodepool
 /usr/local/jenkins/slave_scripts/install-distro-packages.sh
-sudo pip install .
+sudo pip3 install .
 
 bash -xe ./tools/zuul-nodepool-integration/start.sh