Remove 3rd-party Puppet "firewall" module dependency

[matze]

Module firewall has been introduced as dependency in infrastructure together with module postgresql, the latter of which being the entity using it. Module postgresql, however, does not depend on module firewall any more:

$ grep -R firewall * | grep -v '^\(Binary file \)\?modules/firewall'
dependencies:modules/firewall = infrastructure-puppetlabs-firewall hg:7005ec47f8a7 git:7b8ddb0
modules/nagios/templates/cgi.cfg.erb:# secure domain (i.e., behind a firewall) to see the current status
Binary file modules/postgresql/.hg/store/data/manifests/globals.pp.i matches
Binary file modules/postgresql/.hg/store/data/spec/system/server__spec.rb.i matches
modules/postgresql/.hg/store/fncache:data/spec/acceptance/firewall_default_parameters_spec.rb.i
modules/postgresql/.hg/store/fncache:data/manifests/server/firewall.pp.i
Binary file modules/postgresql/.hg/store/undo matches
modules/postgresql/.fixtures.yml:    firewall: "https://github.com/puppetlabs/puppetlabs-firewall.git"
modules/postgresql/CHANGELOG.md:This release removes the uninstall ability from the module, removes the firewall
modules/postgresql/CHANGELOG.md:- Removal of firewall management.

Hence we can remove the dependency from the infrastructure repository.

[abpbot]

A commit referencing this issue has landed:
​Issue 4121 - Remove dependency for module puppetlabs-firewall