patman: Quieten down the alias checking

When a tag is used in a patch subject (e.g. "tag: rest of message") and
it cannot be found as an alias, patman currently reports a fatal error,
unless -t is provided, in which case it reports a warning.

Experience suggest that the fatal error is not very useful. Instead,
default to reporting a warning, with -t tell patman to ignore it
altogether.

Signed-off-by: Simon Glass <sjg@chromium.org>

tools/patman/func_test.py

@@ -186,7 +186,7 @@ class TestFunctional(unittest.TestCase):
             - Commit-notes
         """
         process_tags = True
-        ignore_bad_tags = True
+        ignore_bad_tags = False
         stefan = b'Stefan Br\xc3\xbcns <stefan.bruens@rwth-aachen.de>'.decode('utf-8')
         rick = 'Richard III <richard@palace.gov>'
         mel = b'Lord M\xc3\xablchett <clergy@palace.gov>'.decode('utf-8')