Description of problem:
Adding or removing non-existent channel with rhn-channel tools causes traceback instead of sane warning message.  

Version-Release number of selected component (if applicable):
1.7.14-1.el6 - It's a regression!!! (1.6.47-1.el6 was flawless)

How reproducible:
100%

Steps to Reproduce:
1. Run rhn-channel -u admin -p pass {-a|-r} -c nonsense
2. Error is displayed
3. Traceback is logged
  
Actual results:
# rhn-channel -u admin -p pass -a -c nonsense
An error has occurred:
<type 'exceptions.TypeError'>
See /var/log/up2date for more information

/var/log/up2date:
[Fri Mar 16 12:05:04 2012] up2date
Traceback (most recent call last):
  File "/usr/sbin/rhn-channel", line 162, in <module>
    systemExit(1, e)
  File "/usr/sbin/rhn-channel", line 46, in systemExit
    sys.stderr.write(rhncli.utf8_encode(msg)+'\n')
<type 'exceptions.TypeError'>: unsupported operand type(s) for +: 'CommunicationError' and 'str'


Expected results:
# rhn-channel -u admin -p pass -a -c nonsense
Error communicating with server. The message was:

Error Message:
    Channel nonsense does not exist?
Error Class Code: 40
Error Class Info: The specified channel does not exist.
Explanation: 
     An error has occurred while processing your request. If this problem
     persists please enter a bug report at bugzilla.redhat.com.
     If you choose to submit the bug report, please be sure to include
     details of what you were trying to do when this error occurred and
     details on how to reproduce this problem.

Additional info: