csmock: simplify handling of --known-false-positives

This is a follow-up to the previous commit that further simplifies
the code with no intended changes in behavior.

Closes: #118

py/csmock

@@ -895,15 +895,14 @@ key event (defaults to 3).")
  help="use shell command to build the given tarball (instead of SRPM)")
 
  # --known-false-positives
- if os.path.exists(DEFAULT_KNOWN_FALSE_POSITIVES):
- default_kfp = DEFAULT_KNOWN_FALSE_POSITIVES
- default_kfp_text = " (defaults to \"%s\")" % default_kfp
- else:
+ default_kfp = DEFAULT_KNOWN_FALSE_POSITIVES
+ default_kfp_text = f'defaults to "{default_kfp}"'
+ if not os.path.exists(default_kfp):
  default_kfp = ""
- default_kfp_text = " (defaults to \"%s\" if available)" % DEFAULT_KNOWN_FALSE_POSITIVES
+ default_kfp_text += " if available"
  parser.add_argument(
  "--known-false-positives", default=default_kfp,
- help=("suppress known false positives loaded from the given file" + default_kfp_text))
+ help=f"suppress known false positives loaded from the given file ({default_kfp_text})")
 
  csmock.common.util.add_paired_flag(
  parser, "use-login-shell",