Fix new dib-lint errors

The dib 2.34.0 release uncapped hacking and has found some new minor
issues.  Add missing readmes and fix whitespace.

Change-Id: Ia05e54c26988774bf03b0764a6df5e60e8ddaca8

nodepool/elements/control-plane-minimal/README.rst

@@ -0,0 +1,4 @@
+control-plane-minimal
+---------------------
+
+Essential packages for an OpenDev infra control-plane image.

nodepool/elements/infra-package-needs/README.rst

@@ -0,0 +1,4 @@
+infra-package-needs
+-------------------
+
+Install required packages for a OpenDev infra host

nodepool/elements/openstack-repos/extra-data.d/50-create-repo-list

@@ -75,5 +75,6 @@ def main():
             projects_list.write("%(name)s git %(location)s "
                                 "%(url)s %(ref)s\n" % args)
 
+
 if __name__ == '__main__':
     main()