Description of problem:
Using the API:
curl -k -v https://admin:admin@katello/katello/api/users/1000

When user 1000 does not exist, returns a 500, instead of a 404 as expected. 

Version-Release number of selected component (if applicable):
katello-glue-foreman-0.1.318-1.el6cf.noarch
katello-qpid-broker-key-pair-1.0-1.noarch
katello-cli-0.1.112-1.el6cf.noarch
katello-glue-candlepin-0.1.318-1.el6cf.noarch
katello-agent-0.17-1.el6.noarch
katello-cli-common-0.1.112-1.el6cf.noarch
katello-certs-tools-1.0.7-1.el6_3.noarch
katello-selinux-0.1.10-1.el6.noarch
katello-candlepin-cert-key-pair-1.0-1.noarch
katello-glue-pulp-0.1.318-1.el6cf.noarch
katello-all-0.1.318-1.el6cf.noarch
katello-0.1.318-1.el6cf.noarch
katello-configure-0.1.111-1.el6cf.noarch
katello-common-0.1.318-1.el6cf.noarch
katello-qpid-client-key-pair-1.0-1.noarch


How reproducible:
Always

Steps to Reproduce:
1. Use above curl command
2.
3.
  
Actual results:
500 return

Expected results:
404 return