Remove un-needed imports

Author: csm10495

Lib/concurrent/futures/process.py

@@ -58,7 +58,6 @@
 import weakref
 from functools import partial
 import itertools
-import signal
 import sys
 from traceback import format_exception
 

Lib/test/test_concurrent_futures/test_process_pool.py

@@ -1,7 +1,6 @@
 import multiprocessing
 import os
 import queue
-import signal
 import sys
 import threading
 import time