RDO-instack-undercloud: instack-install-undercloud exists with error "ImportError: No module named six".


Environment:
instack-undercloud-2.0.0-dev1662.el7.centos.noarch


Steps to reproduce:
1. Install the instack-undercloud package.
2. Run instack-install-undercloud

Result:
+ echo puppet-tuskar Wed Apr 22 13:02:43 EDT 2015 Running /tmp/tmp8yhb3O/extra-data.d/10-merge-svc-map-files
puppet-tuskar Wed Apr 22 13:02:43 EDT 2015 Running /tmp/tmp8yhb3O/extra-data.d/10-merge-svc-map-files
+ target_tag=10-merge-svc-map-files
+ date +%s.%N
+ /tmp/tmp8yhb3O/extra-data.d/10-merge-svc-map-files
Traceback (most recent call last):
  File "/tmp/tmp8yhb3O/extra-data.d/10-merge-svc-map-files", line 18, in <module>
    import six
ImportError: No module named six
INFO: 2015-04-22 13:02:43,902 -- ############### End stdout/stderr logging ###############
ERROR: 2015-04-22 13:02:43,903 --     Hook FAILED.
ERROR: 2015-04-22 13:02:43,903 -- Failed running command ['dib-run-parts', u'/tmp/tmp8yhb3O/extra-data.d']


Expected result:
The undercloud should be installed with no errors.


Workaround:
yum install python-six