fix: use getloing value --unknown-- on error.

In case there is a real user with name unknown, Unlikely for account to
to have dashes in name.

Author: rouilj

roundup/logcontext.py

@@ -155,7 +155,7 @@ def wrapper(*args, **kwargs):
                 try:
                     login = os.getlogin()
                 except OSError:
-                    login = "unknown"
+                    login = "--unknown--"
                 reason = "roundup-admin(%s): %s" % (login, args[1][:2])
             elif location.startswith("file://"):
                 reason = location