fix pylint warnings

note that:
 - _version is a generated/vendored file, so we just disable all
 - ssl.OP_NO_TLSv1 and OP_NO_TLSv1_1 are not detected by pylint, so we add
   a local ignore

kedifa/_version.py

-
+# pylint: disable-all
 # This file helps to compute a version number in source trees obtained from
 # git-archive tarball (such as those provided by githubs download-from-tag
 # feature). Distribution tarballs (built by setup.py sdist) and build

kedifa/app.py

@@ -19,7 +19,6 @@
 # See https://www.nexedi.com/licensing for rationale and options.
 
 from cryptography import x509
-from cryptography.hazmat.primitives.serialization import Encoding
 from threading import local
 from wsgiref.simple_server import make_server
 import caucase.exceptions
@@ -170,7 +169,7 @@ class SQLite3Storage(local):
     return bool(result)
 
   def reserveId(self):
-    for trynum in range(10):
+    for _ in range(10):
       reserved_id = ''.join(
         random.choice(
           string.ascii_lowercase + string.digits) for _ in range(32))
@@ -490,7 +489,7 @@ def getSSLContext(server_key_path, ca_certificate_path, crl_path):
   # ssl_context.verify_flags = ssl.VERIFY_CRL_CHECK_LEAF
   # ssl_context.load_verify_locations(cafile=crl_path)
 
-  ssl_context.options |= ssl.OP_NO_TLSv1 | ssl.OP_NO_TLSv1_1
+  ssl_context.options |= ssl.OP_NO_TLSv1 | ssl.OP_NO_TLSv1_1 # pylint:disable=no-member
   ssl_context.verify_mode = ssl.CERT_OPTIONAL
   ssl_context.load_verify_locations(cafile=ca_certificate_path)
   ssl_context.load_cert_chain(server_key_path)

kedifa/test.py

@@ -31,7 +31,6 @@ import requests
 import requests.exceptions
 import shutil
 import signal
-import sys
 import tarfile
 import tempfile
 import time
@@ -328,9 +327,9 @@ ez+ONyvetfvjD8cxyQ==
     self.kedifa_runtime.start()
     self.assertTrue(self.kedifa_runtime.is_alive())
 
-    # give 5s for KeDiFa to be available
+    # give KeDiFa some time to be available
     b = time.time()
-    for i in range(100):
+    for _ in range(100):
       try:
         self.requests_get(self.kedifa_url + 'ping')
       except BaseException: