Description of problem:
Disabling of the scap result deletion policy also resets retention period to the default (90 days). The retention period is being reset either using webui or API. 


Version-Release number of selected component (if applicable):
spacewalk-java-2.0.2-46.el5sat


How reproducible:
@webUI
@API


Steps to Reproduce:
API:
1. >>> client.org.setPolicyForScapResultDeletion(key, 1, {'retention_period': 15, 'enabled': False})
1
2. >>> client.org.getPolicyForScapResultDeletion(key,1)
{'retention_period': 0, 'enabled': False}

WEBUI:
1. Admin -> Organization -> <selected organization> -> Configuration:
check Allow Deletion of SCAP Results: [v] and then you can set value of Allow Deletion After (period in days). And hit "Update Organization" button.
2. uncheck Allow Deletion of SCAP Results: [_] and hit "Update Organization" button.


3. In both situations custom value of retention_period/"Allow Deletion After (period in days)" is discarded and replaced by the default one.


Actual results:
disabling the policy also resets retention period to the default


Expected results:
when disabling the policy retention period remains the same