Description of problem:

In order to delete a keyname/value pair from a system's custom information field, one must provide at least the keyname as an argument. However the cli does not make this requirement explicit which can be a bit confusing.

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

* candlepin-0.7.23-1.el6_3.noarch
* candlepin-tomcat6-0.7.23-1.el6_3.noarch
* elasticsearch-0.19.9-5.el6_3.noarch
* katello-candlepin-cert-key-pair-1.0-1.noarch
* katello-certs-tools-1.2.1-1h.el6_3.noarch
* katello-cli-1.2.1-11h.el6_3.noarch
* katello-cli-common-1.2.1-11h.el6_3.noarch
* katello-common-1.2.1-12h.el6_3.noarch
* katello-configure-1.2.3-1h.el6_3.noarch
* katello-glue-candlepin-1.2.1-12h.el6_3.noarch
* katello-headpin-1.2.1-12h.el6_3.noarch
* katello-headpin-all-1.2.1-12h.el6_3.noarch
* katello-selinux-1.2.1-2h.el6_3.noarch
* thumbslug-0.0.28-1.el6_3.noarch
* thumbslug-selinux-0.0.28-1.el6_3.noarch

How reproducible:


Steps to Reproduce:
1. Create a random organization with a random set of environments
2. Register a system to this organization
3. ssh to the system and open the katello/headpin shell
4. Obtain the uuid or the name for the newly registered system
5. Check the current custom information attached to this system
6. Add a new custom information to the system:
   system add_custom_info <random name> --name <system_name> --keyname 'secret question' --value 'secret answer' (or use the system's uuid)
7. Add another custom information to the system:
   system add_custom_info <random name> --name <system_name> --keyname 'secret location' --value 'secret place' (or use the system's uuid)
8. Delete one of the custom information fields:
   system remove_custom_info <random name> --name <system_name>
  
Actual results:

Couldn't find custom info

Expected results:

Some type of notification stating that at least the keyname is required to remove a keyname/value pair.


Additional info: