Fixes issue due to missing double quote

Error: Could not find template 'gitlab/unicorn.rb.${gitlab::gitlab_branch}.erb' at /etc/puppet/modules/gitlab/manifests/setup.pp:76 on node gitlab.localdomain
Error: Could not find template 'gitlab/unicorn.rb.${gitlab::gitlab_branch}.erb' at /etc/puppet/modules/gitlab/manifests/setup.pp:76 on node gitlab.localdomain
Removes unused postfix config file
Removes todo to remove wildcard in nginx config (won't fix https://github.com/spuder/puppet-gitlab/issues/20)
Fixes login for git user http://unix.stackexchange.com/questions/96892/what-does-adduser-disabled-login-do/96897#96897
Code comments clean up
Removes erroneous params references