Description of problem:
If a user uses subscription-manager to try and subscribe to a nonexistent pool in katello, the error returned appears to be raw json, versus the properly formatted error message itself.  Modifying /etc/rhsm/rhsm.conf to point to the candlepin server itself results in a a correct error message.

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


How reproducible:


Steps to Reproduce:
1. Assure there are (valid) subscription pools in Katello.
2. Register a system to katello
3. Attempt to subscribe to a pool using an /invalid/ pool id... i.e., 'subscription-manager subscribe --pool=ff808081321b487e01321b5a94640010'
4. View results
  
Actual results:
{"displayMessage":"Subscription pool ff808081321b487e01321b5a94640010 does not exist."}

Expected results:
Subscription pool ff808081321b487e01321b5a94640010 does not exist.


Additional info:
To reiterate, if user modifies rhsm.conf to point to the appropriate respective endpoint and port for the underlying candlepin, the proper error message appears.