Fixes to nodepool installation on jenkins-dev.o.o

The patch to add nodepool to jenkins-dev (https://review.openstack.org/#/c/57333)
did not work.

There were a few issues with it:
  1. jenkins-dev.pp was passing literal strings to the nodepool module, instead it
     should be passing in the variables.
  2. jenkins-dev.pp was calling ::nodepool but puppet seems to think that it wants
     ::openstack_project::nodepool due to puppet's scoping weirdness :(
  3. The script to build nodepool machines needed the jenkins_dev_ssh_key.

Fixes to above issues:
  1. This is trivial, just passed the variables thru instead of literal strings.
  2. The nodepool.pp module is renamed to nodepool_prod.pp to prevent the scoping problem.
  3. We use the dev jenkins ssh key with dev nodepool by allowing the nodepool module
     to pass arbitrary env settings through the defaults file.

Change-Id: Id91053212f088079ff1b0f06ebdce5c381f5cd19
Merge "Fixes to nodepool installation on jenkins-dev.o.o"