Description of problem: Multiple test cases in pulp_rpm/plugins/test/unit/test_config.py are importing code that is not valid on RHEL5.  


Version-Release number of selected component (if applicable):


How reproducible:  easily


Steps to Reproduce:
1. Run the unit tests for pulp_rpm on RHEL 5
2. observe the log file

Actual results:
======================================================================
ERROR: test_invalid (test_config.ValidateTests)
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Traceback (most recent call last):
  File "/home/jenkins/workspace/pulp_all-rhel5/pulp_rpm/plugins/test/unit/test_config.py", line 43, in test_invalid
    result, error = config_validate.validate(config)
  File "/home/jenkins/workspace/pulp_all-rhel5/pulp_rpm/plugins/pulp_rpm/plugins/importers/yum/config_validate.py", line 31, in validate
    importer_config.validate_config(config)
  File "/home/jenkins/workspace/pulp_all-rhel5/pulp/platform/src/pulp/plugins/util/importer_config.py", line 54, in validate_config
    potential_exception = InvalidConfig()
  File "/home/jenkins/workspace/pulp_all-rhel5/pulp/platform/src/pulp/plugins/util/importer_config.py", line 31, in __init__
    super(InvalidConfig, self).__init__()
TypeError: super() argument 1 must be type, not classobj

======================================================================
ERROR: test_valid (test_config.ValidateTests)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/home/jenkins/workspace/pulp_all-rhel5/pulp_rpm/plugins/test/unit/test_config.py", line 32, in test_valid
    result, error = config_validate.validate(config)
  File "/home/jenkins/workspace/pulp_all-rhel5/pulp_rpm/plugins/pulp_rpm/plugins/importers/yum/config_validate.py", line 31, in validate
    importer_config.validate_config(config)
  File "/home/jenkins/workspace/pulp_all-rhel5/pulp/platform/src/pulp/plugins/util/importer_config.py", line 54, in validate_config
    potential_exception = InvalidConfig()
  File "/home/jenkins/workspace/pulp_all-rhel5/pulp/platform/src/pulp/plugins/util/importer_config.py", line 31, in __init__
    super(InvalidConfig, self).__init__()
TypeError: super() argument 1 must be type, not classobj


Expected results:
Unit tests should run successfully RHEL 5 and a build on RHEL 5 should complete successfully.  If a unit test should not be run on RHEL 5 it should be separated out in the run-tests.py so that it will not run on RHEL 5

Additional info: