Fixing import error for tempfile

A change was made to add extra logging whenever pip log files cannot be added. 

Here is the changeset that caused the issue:  https://github.com/pypa/pip/commit/8ebc7a316016c4eb01cb77c8df1fe538c7bddf2a#pip/basecommand.py

pip/basecommand.py

@@ -4,6 +4,7 @@ import os
 from pkgutil import walk_packages
 import socket
 import sys
+import tempfile
 import traceback
 import time