Remove unused imports, from python scripts. (facebook#4057)

Summary:
Also remove redefined variable.
As reported on https://lgtm.com/projects/g/facebook/rocksdb/
Closes facebook#4057

Differential Revision: D8648342

Pulled By: ajkr

fbshipit-source-id: afd2ba84d1364d316010179edd44777e64ca9183

buckifier/buckify_rocksdb.py

@@ -3,14 +3,11 @@
 from __future__ import print_function
 from __future__ import unicode_literals
 from targets_builder import TARGETSBuilder
-from optparse import OptionParser
 import os
 import fnmatch
 import sys
-import tempfile
 
 from util import ColorString
-import util
 
 # tests to export as libraries for inclusion in other projects
 _EXPORTED_TEST_LIBS = ["env_basic_test"]

coverage/parse_gcov_output.py

@@ -1,4 +1,3 @@
-import optparse
 import re
 import sys
 

tools/db_crashtest.py

@@ -1,10 +1,8 @@
 #! /usr/bin/env python
 import os
-import re
 import sys
 import time
 import random
-import logging
 import tempfile
 import subprocess
 import shutil
@@ -291,7 +289,7 @@ def whitebox_crash_main(args, unknown_args):
             }
         else:
             # normal run
-            additional_opts = additional_opts = {
+            additional_opts = {
                 "kill_random_test": None,
                 "ops_per_thread": cmd_params['ops_per_thread'],
             }