Description of problem:
We cannot write scripts to use redhat-support-tool because we cannot detect errors properly.  All failures with the tool appear to exit with a 0 exit code and write the error to standard output instead of standard error.

Version-Release number of selected component (if applicable):
redhat-support-tool-0.10.2-1.el8_0.noarch

How reproducible: Very
Steps to Reproduce:

# with invalid file, exits 0 on error
[root@ibm-p8-kvm-03-guest-02 ~]# redhat-support-tool addattachment /dev/null -c abcd
ERROR: /dev/null is not a valid file.
[root@ibm-p8-kvm-03-guest-02 ~]# echo $?
0 # I expect >=1

# with no configured userid, exits 0 on error
[root@ibm-p8-kvm-03-guest-02 ~]# redhat-support-tool kb abcd
Please enter your RHN user ID:
Unable to find a KB with an ID of abcd
[root@ibm-p8-kvm-03-guest-02 ~]# echo $?
0

# with user, no known kb article, exits 0
[root@ibm-p8-kvm-03-guest-02 ~]# redhat-support-tool kb abcd
Unable to fulfill request with support services API. Reason: Not Found
[root@ibm-p8-kvm-03-guest-02 ~]# echo $?
0

# all errors appear to be written to stdout, not stderr
[root@ibm-p8-kvm-03-guest-02 ~]# redhat-support-tool kb abcd 1> /dev/null
# nothing written to stderr...


Expected results:
All failed commands should exit with a non-zero exit code and write their errors to STDERR, not STDOUT.