simplify pip_install.py

tools/pip_install.py

@@ -6,10 +6,7 @@
 from __future__ import absolute_import
 from __future__ import print_function
 
-import contextlib
 import os
-import re
-import shutil
 import subprocess
 import sys
 import tempfile
@@ -17,17 +14,6 @@ import tempfile
 import readlink
 
 
-# Once this code doesn't need to support Python 2, we can simply use
-# tempfile.TemporaryDirectory.
-@contextlib.contextmanager
-def temporary_directory():
-    dirpath = tempfile.mkdtemp()
-    try:
-        yield dirpath
-    finally:
-        shutil.rmtree(dirpath)
-
-
 def find_tools_path():
     return os.path.dirname(readlink.main(__file__))
 
@@ -49,7 +35,7 @@ def pip_install_with_print(args_str, env=None):
 def main(args):
     tools_path = find_tools_path()
 
-    with temporary_directory() as working_dir:
+    with tempfile.TemporaryDirectory as working_dir:
         if os.environ.get('CERTBOT_NO_PIN') == '1':
             # With unpinned dependencies, there is no constraint
             pip_install_with_print(' '.join(args))