Make creation of temporary file and directory more portable. Also made cleanup

code use proper functions to get paths.

Changed the name of tar file that is searched for to be absolute (i.e., not use
os.extsep) since filename is locked in based on name of file in CVS
(testtar.tar).

Closes bug #731403 .

Lib/test/test_tarfile.py

 import sys
 import os
 import shutil
+import tempfile
 
 import unittest
 import tarfile
@@ -21,9 +22,9 @@ except ImportError:
 def path(path):
     return test_support.findfile(path)
 
-testtar = path("testtar" + os.extsep + "tar")
-tempdir = path("testtar" + os.extsep + "dir")
-tempname = path("testtar" + os.extsep + "tmp")
+testtar = path("testtar.tar")
+tempdir = os.path.join(tempfile.gettempdir(), "testtar" + os.extsep + "dir")
+tempname = test_support.TESTFN
 membercount = 10
 
 def tarname(comp=""):
@@ -265,10 +266,10 @@ def test_main():
             os.remove(tarname("gz"))
         if bz2:
             os.remove(tarname("bz2"))
-        if os.path.exists(tempdir):
-            shutil.rmtree(tempdir)
-        if os.path.exists(tempname):
-            os.remove(tempname)
+        if os.path.exists(dirname()):
+            shutil.rmtree(dirname())
+        if os.path.exists(tmpname()):
+            os.remove(tmpname())
 
 if __name__ == "__main__":
     test_main()