#17448: Make test_sax skip if there are no xml parsers.

Patch by Rafael Santos.
diff --git a/Lib/test/test_sax.py b/Lib/test/test_sax.py
index bfa7d72..3efd972 100644
--- a/Lib/test/test_sax.py
+++ b/Lib/test/test_sax.py
@@ -3,11 +3,12 @@
 
 from xml.sax import make_parser, ContentHandler, \
                     SAXException, SAXReaderNotAvailable, SAXParseException
+import unittest
 try:
     make_parser()
 except SAXReaderNotAvailable:
     # don't try to test this module if we cannot create a parser
-    raise ImportError("no XML parsers available")
+    raise unittest.SkipTest("no XML parsers available")
 from xml.sax.saxutils import XMLGenerator, escape, unescape, quoteattr, \
                              XMLFilterBase
 from xml.sax.expatreader import create_parser
@@ -18,7 +19,6 @@
 import shutil
 from test import support
 from test.support import findfile, run_unittest
-import unittest
 
 TEST_XMLFILE = findfile("test.xml", subdir="xmltestdata")
 TEST_XMLFILE_OUT = findfile("test.xml.out", subdir="xmltestdata")