tidy up the gemfile
tidy up the gemfile

* Moves beaker dependencies to system_tests group
* pin puppetlabs_spec_helper and rspec-puppet to compatible versions, which should minimize future breakage
* removed explicit dependency on rake

xaque208/puppet-nginx,voxpupuli/puppet-nginx,xaque208/puppet-nginx,bastelfreak/puppet-nginx,jfryman/puppet-nginx,bastelfreak/puppet-nginx,icann-dns/puppet-nginx,hbog/puppet-nginx,hbog/puppet-nginx,icann-dns/puppet-nginx,blackcobra1973/puppet-nginx,jfryman/puppet-nginx,raphink/puppet-nginx,bulletproofnetworks/puppet-nginx,voxpupuli/puppet-nginx,bulletproofnetworks/puppet-nginx,apa-it/puppet-nginx,apa-it/puppet-nginx,blackcobra1973/puppet-nginx