Removed imports left unused after Py{OpenSSL,ASN1}

Commits 533f61f67a and
8b841bc9e3 left some imports unused while
swithing to PyOpenSSL and PyASN1 -- this commit removes these imports.

libmproxy/certutils.py

@@ -1,4 +1,4 @@
-import subprocess, os, tempfile, ssl, hashlib, socket, re
+import subprocess, os, ssl, hashlib, socket
 from pyasn1.type import univ, constraint, char, namedtype, tag
 from pyasn1.codec.der.decoder import decode
 import OpenSSL

test/test_utils.py

@@ -1,4 +1,4 @@
-import textwrap, os, re, json
+import textwrap, re, json
 import libpry
 from libmproxy import utils