Description of problem:
"spacewalk-channel" exit code is always 0 even when it fails.

Version-Release number of selected component (if applicable):
rhn-setup-0.4.20-46.el5

How reproducible:
Always

Steps to Reproduce:
1.Get RHEL5 system
2.Register to Satellite
3.spacewalk-channel --list
rhel-i386-server-5
4. Try to unsubscribe from a channel that it not in the list above.
spacewalk-channel -r -u ${USER} -p ${PASS} -c rhn-tools-rhel-i386-server-6
6. No error,info or  warning message.
5. echo $?  
Actual results:
0

Expected results:
1, 127 ... etc.

Additional info:
Many other inappropriate error messages.

Examples:
#### In case -a (-r) parameter is omitted. ###
[root@dell~]# spacewalk-channel -u admin -p admin -c rhn-tools-rhel-i386-server-6
Traceback (most recent call last):
  File "/usr/sbin/spacewalk-channel", line 92, in ?
    main()
  File "/usr/sbin/spacewalk-channel", line 86, in main
    s = rhnserver.RhnServer()
NameError: global name 'rhnserver' is not defined

The Error message is misleading.


#### Execute without params ####

[root@dell ~]# spacewalk-channel
ERROR: username is required

Does not say much as well. ( --list option does not need username and password)