cleanup: Ensure code is pyflakes-clean for CI

qa/rpc-tests/wallet_anchorfork.py

@@ -4,7 +4,6 @@
 # file COPYING or http://www.opensource.org/licenses/mit-license.php.
 
 from test_framework.test_framework import BitcoinTestFramework
-from test_framework.authproxy import JSONRPCException
 from test_framework.util import assert_equal, initialize_chain_clean, \
     start_nodes, stop_nodes, connect_nodes_bi, \
     wait_and_assert_operationid_status, wait_bitcoinds

qa/rpc-tests/zkey_import_export.py

@@ -9,7 +9,6 @@ from test_framework.util import assert_equal, assert_greater_than, start_nodes,\
     initialize_chain_clean, connect_nodes_bi, wait_and_assert_operationid_status
 
 import logging
-import time
 import math
 
 logging.basicConfig(format='%(levelname)s:%(message)s', level=logging.INFO)

qa/zcash/create_benchmark_archive.py

@@ -5,7 +5,6 @@ import plyvel
 import progressbar
 import os
 import stat
-import struct
 import subprocess
 import sys
 import tarfile

src/test/bctest.py

@@ -3,7 +3,6 @@
 # file COPYING or http://www.opensource.org/licenses/mit-license.php.
 
 import subprocess
-import os
 import json
 import sys
 

zcutil/release-notes.py

@@ -1,4 +1,4 @@
-import re, sys, os, os.path
+import re, os, os.path
 import subprocess
 import argparse
 from itertools import islice