Description of problem:
Not able to set default SLA for an ORG in CLI

Version-Release number of selected component (if applicable):
* candlepin-0.8.7-1.el6.noarch
* candlepin-cert-consumer-ibm-x3655-02.ovirt.rhts.eng.bos.redhat.com-1.0-1.noarch
* candlepin-tomcat6-0.8.7-1.el6.noarch
* elasticsearch-0.19.9-7.el6.noarch
* katello-candlepin-cert-key-pair-1.0-1.noarch
* katello-certs-tools-1.4.2-1.el6.noarch
* katello-cli-1.4.2-1.git.48.441089b.el6.noarch
* katello-cli-common-1.4.2-1.git.48.441089b.el6.noarch
* katello-common-1.4.2-1.git.352.c97daf2.el6.noarch
* katello-configure-1.4.3-1.git.21.0134f7d.el6.noarch
* katello-glue-candlepin-1.4.2-1.git.352.c97daf2.el6.noarch
* katello-glue-elasticsearch-1.4.2-1.git.352.c97daf2.el6.noarch
* katello-headpin-1.4.2-1.git.352.c97daf2.el6.noarch
* katello-headpin-all-1.4.2-1.git.352.c97daf2.el6.noarch
* Katello-Katello-Installation-RegisterRHNClassic-1.1-3.noarch
* Katello-Katello-Sanity-ImportKeys-1.2-1.noarch
* katello-repos-1.4.2-1.el6.noarch
* katello-selinux-1.4.3-1.git.3.ce8227b.el6.noarch
* thumbslug-0.0.27-1.el6.noarch
* thumbslug-selinux-0.0.27-1.el6.noarch


How reproducible:
Always

Steps to Reproduce:
1. Install headpin-nightly
2. Upload a manifest
3. Try setting default SLA for an ORG in UI.  Options shown are 
a. 'Service Level None' 
b. 'No Service Level Preference'
4. Selecting either of the above and saving works fine
5. Now go to cli and log in to headpin shell and try the following commands:
#org update --name ACME_Corporation --servicelevel='No Service Level Preference'
Service level 'No Service Level Preference' is not available to consumers of organization ACME_Corporation.

#org update --name ACME_Corporation --servicelevel='Service Level None'
Service level 'Service Level None' is not available to consumers of organization ACME_Corporation.

Actual results:
An error is thrown as shown above

Expected results:
User should be able to set default SLA for an ORG in CLI

Additional info:
The following command works though:
#org update --name ACME_Corporation --servicelevel='None'
Successfully updated organization [ ACME_Corporation ]

Now it is confusing for the user on what value should be passed to --servicelevel argument in CLI.  May be the --help command needs to instruct user on how to go about using this command.