Remove unneeded imports from bsddb's test_dbshelve.

Lib/bsddb/test/test_dbshelve.py

@@ -2,10 +2,8 @@
 TestCases for checking dbShelve objects.
 """
 
-import sys, os, string
+import os
 import tempfile, random
-from pprint import pprint
-from types import *
 import unittest
 
 from bsddb import db, dbshelve