warnings was imported at module scope, no need to import again

Lib/test/regrtest.py

@@ -684,7 +684,7 @@ def dash_R(the_module, test, indirect_test, huntrleaks):
 
 def dash_R_cleanup(fs, ps, pic):
     import gc, copy_reg
-    import _strptime, linecache, warnings, dircache
+    import _strptime, linecache, dircache
     import urlparse, urllib, urllib2, mimetypes, doctest
     import struct, filecmp
     from distutils.dir_util import _path_created