Description of problem:
Spacewalk-clone-by-date can not proceed if configuration file is used and option blacklist or removelist are not present.

Version-Release number of selected component (if applicable):
spacewalk-utils-2.3.2-5

How reproducible:
Always

Steps to Reproduce:
1. Have the following configuration file test.conf:
    {
     "username":"admin",
     "password":"redhat",
     "to_date": "2011-10-01",
     "errata": ["RHBA-2014:1646", "RHSA-2014:1635"],
     "channels":[
                 {
                    "rhel-x86_64-server-6":"clone-rhel-x86_64-server-6"
                 }
               ]
    }

2. spacewalk-clone-by-date -c test.conf

Actual results:
blacklist  is not formatted correctly


Additional info:
In  case options blacklist and removelist are present and even empty, the spacewalk-clone-by-date tool works as expected.

    {
     "username":"admin",
     "password":"redhat",
     "to_date": "2011-10-01",
     "errata": ["RHBA-2014:1646", "RHSA-2014:1635"],
     "blacklist":{},
     "removelist":{},
     "channels":[
                 {
                    "rhel-x86_64-server-6":"clone-rhel-x86_64-server-6"
                 }
               ]
    }