Show warnings about un-stat-able files even with verbosity == 0

I get that this is some kind of a grey area due to the underlying race
condition (files vanishing after they have been scanned). However, if we
can't stat() a file it can have many different causes -- the file being
vanished is just one of them. Since this tool is meant to help detect
bit rot and corrupt file systems, I'd rather be informed about
un-stat-able files.

src/bitrot.py

@@ -201,7 +201,6 @@ class Bitrot(object):
                     # The file disappeared between listing existing paths and
                     # this run or is (temporarily?) locked with different
                     # permissions. We'll just skip it for now.
-                    if self.verbosity:
                     print(
                         '\rwarning: `{}` is currently unavailable for '
                         'reading: {}'.format(