It's a current issue.  Without that line, you get this:

    jpartlow@percival:~/work/puppet$ be puppet agent -t --server puppetmaster
    Info: Creating a new SSL key for percival.corp.puppetlabs.net
    Info: Caching certificate for ca
    Info: Creating a new SSL certificate request for percival.corp.puppetlabs.net
    Info: Certificate Request fingerprint (SHA256): 20:18:5A:F0:3B:A0:BE:76:6B:03:71:ED:BD:EF:47:04:F1:49:3F:BD:63:AC:42:3D:7E:0F:66:3F:08:F9:70:C9
    Info: Caching certificate for percival.corp.puppetlabs.net
    Info: Caching certificate_revocation_list for ca
    Info: Retrieving plugin
    Error: /File[/home/jpartlow/.puppet/var/lib]: Could not evaluate: Could not retrieve information from environment production source(s) puppet://puppetmaster/plugins
    Info: Caching catalog for percival.corp.puppetlabs.net
    Info: Applying configuration version '1374537817'
    Info: Creating state file /home/jpartlow/.puppet/var/state/state.yaml

I'm looking to see if I can find a current Redmine ticket.