Avoid calling decode on str (#16214)

* Avoid calling decode on str

In tests we see this failure:

    AttributeError: 'str' object has no attribute 'decode'. Did you mean: 'encode'?

This implies that the strerr value is a str, which you can't decode. I
can't find the specific change, but this implies the result used to be a
byte string and is now decoded elsewhere.

* Update tests/foreman/destructive/test_rename.py

Co-authored-by: Peter Ondrejka <[email protected]>

* Update tests/foreman/destructive/test_rename.py

Co-authored-by: Evgeni Golov <[email protected]>

---------

Co-authored-by: Peter Ondrejka <[email protected]>
Co-authored-by: Jameer Pathan <[email protected]>
Co-authored-by: Evgeni Golov <[email protected]>

tests/foreman/destructive/test_rename.py

@@ -191,7 +191,10 @@ def test_negative_rename_sat_wrong_passwd(module_target_sat):
         f'satellite-change-hostname -y {new_hostname} -u {username} -p {password}'
     )
     assert result.status == 1
-    assert BAD_CREDS_MSG in result.stderr[1].decode()
+    assert BAD_CREDS_MSG in result.stderr
+    # assert no changes were made
+    hostname_result = module_target_sat.execute('hostname')
+    assert original_name == hostname_result.stdout.strip(), "Invalid hostame assigned"
 
 
 @pytest.mark.stubbed