Fixes issue #269 by removing an erroneous "if sbyfile" check.

This commit removes an erroneous "if sbyfile" that would turn '-f' into a no-op
for stdin input files. Presumably this check was originally intended to handle
the case of stdin input file and no specified workdir (which uses a temporary
workdir). In the current version the check is redundant for this particular
case. The check is erroneous in the case of stdin input file and a specified
workdir, so we simply remove the check.

sbysrc/sby.py

@@ -422,8 +422,7 @@ def start_task(taskloop, taskname):
 
  if opt_force and not reusedir:
  early_log(my_workdir, f"Removing directory '{os.path.abspath(my_workdir)}'.")
- if sbyfile:
- shutil.rmtree(my_workdir, ignore_errors=True)
+ shutil.rmtree(my_workdir, ignore_errors=True)
 
  if reusedir:
  pass