Switch to new configparser backport.

setup.py

@@ -131,6 +131,9 @@ install_requires = [
 
     # Linux distribution detection:
     "distro >= 1.4.0",
+
+    # Backported configparser for Python 2:
+    "configparser >= 5.0.1 ; python_version < '3.0'",
 ]
 
 setup_requires = [

src/allmydata/client.py

@@ -2,10 +2,9 @@ import os, stat, time, weakref
 from base64 import urlsafe_b64encode
 from functools import partial
 from errno import ENOENT, EPERM
-try:
-    from ConfigParser import NoSectionError
-except ImportError:
-    from configparser import NoSectionError
+
+# On Python 2 this will be the backported package:
+from configparser import NoSectionError
 
 from foolscap.furl import (
     decode_furl,

src/allmydata/node.py

@@ -13,8 +13,9 @@ from io import StringIO
 import tempfile
 from base64 import b32decode, b32encode
 
-# Python 2 compatibility
-from six.moves import configparser
+# On Python 2 this will be the backported package.
+import configparser
+
 from future.utils import PY2
 if PY2:
     from io import BytesIO as StringIO  # noqa: F811

src/allmydata/scripts/common.py

@@ -8,7 +8,9 @@ from os.path import join
 from future.utils import PY2
 if PY2:
     from future.builtins import str  # noqa: F401
-from six.moves.configparser import NoSectionError
+
+# On Python 2 this will be the backported package:
+from configparser import NoSectionError
 
 from twisted.python import usage
 

src/allmydata/storage_client.py

@@ -31,12 +31,10 @@ the foolscap-based server implemented in src/allmydata/storage/*.py .
 from past.builtins import unicode
 
 import re, time, hashlib
-try:
-    from ConfigParser import (
-        NoSectionError,
-    )
-except ImportError:
-    from configparser import NoSectionError
+
+# On Python 2 this will be the backport.
+from configparser import NoSectionError
+
 import attr
 from zope.interface import (
     Attribute,

src/allmydata/util/configutil.py

@@ -16,13 +16,9 @@ if PY2:
     # we do "r" or "w".
     from builtins import filter, map, zip, ascii, chr, hex, input, next, oct, pow, round, super, bytes, dict, list, object, range, str, max, min  # noqa: F401
 
-if PY2:
-    # In theory on Python 2 configparser also works, but then code gets the
-    # wrong exceptions and they don't get handled. So just use native parser
-    # for now.
-    from ConfigParser import SafeConfigParser
-else:
-    from configparser import SafeConfigParser
+# On Python 2 we use the backport package; that means we always get unicode
+# out.
+from configparser import SafeConfigParser
 
 import attr