Remove unused imports from depot_tools scripts

This change removes some unused imports across depot_tools scripts.

Change-Id: Ic1112065ad1020fc4a3573d3fb9f137915ef439c
Bug: 1475776
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/tools/depot_tools/+/4812185
Auto-Submit: Aravind Vasudevan <aravindvasudev@google.com>
Reviewed-by: Gavin Mak <gavinmak@google.com>
Commit-Queue: Gavin Mak <gavinmak@google.com>

git_cache.py

@@ -8,7 +8,6 @@
 from __future__ import print_function
 
 import contextlib
-import errno
 import logging
 import optparse
 import os

infra_to_superproject.py

@@ -18,11 +18,8 @@ be used to restore your environment to its original state.
 import argparse
 import subprocess
 import os
-import platform
 import sys
 import shutil
-import json
-from pathlib import Path
 
 
 def main(argv):

my_activity.py

@@ -46,7 +46,6 @@ import logging
 from multiprocessing.pool import ThreadPool
 import optparse
 import os
-import subprocess
 from string import Formatter
 import sys
 import urllib

owners_finder.py

@@ -10,7 +10,6 @@ import os
 import copy
 
 
-import git_common
 import gclient_utils
 
 

rdb_wrapper.py

@@ -7,7 +7,6 @@ import contextlib
 import json
 import os
 import requests
-import time
 
 # Constants describing TestStatus for ResultDB
 STATUS_PASS = 'PASS'

setup_color.py

@@ -6,7 +6,6 @@
 from __future__ import print_function
 
 import ctypes
-import os
 import platform
 import subprocess
 import sys

split_cl.py

@@ -12,7 +12,6 @@ import os
 import re
 import subprocess2
 import sys
-import tempfile
 
 import gclient_utils
 import git_footers

subprocess2.py

@@ -9,7 +9,6 @@ In theory you shouldn't need anything else in subprocess, or this module failed.
 
 import codecs
 import errno
-import io
 import logging
 import os
 import subprocess
@@ -19,12 +18,10 @@ import threading
 # Cache the string-escape codec to ensure subprocess can find it later.
 # See crbug.com/912292#c2 for context.
 if sys.version_info.major == 2:
-  import Queue
   codecs.lookup('string-escape')
   # Sends stdout or stderr to os.devnull.
   DEVNULL = open(os.devnull, 'r+')
 else:
-  import queue as Queue
   # pylint: disable=redefined-builtin
   basestring = (str, bytes)
   DEVNULL = subprocess.DEVNULL

upload_metrics.py

@@ -4,7 +4,6 @@
 # found in the LICENSE file.
 
 import http
-import os
 import sys
 import urllib.error
 import urllib.request