fix bug: Sys::Lock::NessyBackend not used
use url specified in GENOME_NESSY_SERVER
use config Nessy URL for testing
use getpwuid in scalar context

Because it was being used in array context, we were generating a
somewhat confusing user_data hash (some values redacted):

    "user_data": {
      "GID": "",
      "": "Mark Burnett",
      "lsf_id": "NONE",
      "requested_at": "Wed, 17 Dec 2014 10:52:31 -0600",
      "lsf_project": "NONE",
      "*": "UID",
      "pid": "19124",
      "host": "HOSTNAME",
      "user": "mburnett",
      "genome_build_id": "NONE",
      "HOMEDIR": "/bin/bash"
    }

With this change, it looks more like this:

    "user_data": {
      "lsf_id": "NONE",
      "requested_at": "Wed, 17 Dec 2014 10:53:58 -0600",
      "lsf_project": "NONE",
      "pid": "19388",
      "host": "HOSTNAME",
      "user": "mburnett",
      "genome_build_id": "NONE"
    }
Merge pull request #353 from mark-burnett/minor-nessy-fixups

Minor nessy fixups