lint-history: fix broken --refs option

Commit 3e153806ff (lint-history: Add --refs argument, 2021-12-30)
added a --refs argument to lint-history, but attempting to inject it
directly into the parsed args fields, bypassing some of the important
logic from FilteringOptions.parse_args() -- particularly the bit where
it translates an empty --refs into a request for '--all' as as list of
references.  I somehow overlooked this in my earlier review.  Fix the
problem now.

Signed-off-by: Elijah Newren <newren@gmail.com>

contrib/filter-repo-demos/lint-history

@@ -160,9 +160,11 @@ if lint_args.relevant:
   exec('def is_relevant(filename):\n  '+'\n  '.join(body.splitlines()),
        globals())
   lint_args.filenames_important = True
-args = fr.FilteringOptions.default_options()
+input_args = []
+if lint_args.refs:
+  input_args = ["--args",] + lint_args.refs
+args = fr.FilteringOptions.parse_args(input_args, error_on_empty = False)
 args.force = True
-args.refs = lint_args.refs if lint_args.refs is not None else []
 if lint_args.filenames_important:
   tmpdir = tempfile.mkdtemp().encode()
   cat_file_process = subprocess.Popen(['git', 'cat-file', '--batch'],