Remove characteristic dependency

Fixes: ticket:3279

pyinstaller.spec

@@ -31,7 +31,6 @@ hidden_imports = [
     'allmydata.introducer',
     'allmydata.stats',
     'cffi',
-    'characteristic',
     'Crypto',
     'packaging.specifiers',
     'six.moves.html_parser',

src/allmydata/_auto_deps.py

@@ -19,7 +19,6 @@ package_imports = [
     ('OpenSSL',          None),
     ('pyasn1',           'pyasn1'),
     ('service-identity', 'service_identity'),
-    ('characteristic',   'characteristic'),
     ('pyasn1-modules',   'pyasn1_modules'),
     ('cryptography',     'cryptography'),
     ('cffi',             'cffi'),