fix a memory errro when using namespace nodes returned from XPath queries,

* python/types.c: fix a memory errro when using namespace nodes
  returned from XPath queries, should fix #521699
* python/tests/Makefile.am python/tests/xpathns.py: add a specific
  regression test for it
Daniel

svn path=/trunk/; revision=3703

python/tests/xpathns.py

@@ -0,0 +1,29 @@
+#!/usr/bin/python -u
+#
+import libxml2
+
+expect=' xmlns:a="urn:whatevar"'
+
+# Memory debug specific
+libxml2.debugMemory(1)
+
+d = libxml2.parseDoc("<a:a xmlns:a='urn:whatevar'/>")
+res=""
+for n in d.xpathEval("//namespace::*"):
+    res = res + n.serialize()
+d.freeDoc()
+
+if res != expect:
+    print "test5 failed: unexpected output"
+    print res
+del res
+del d
+del n
+# Memory debug specific
+libxml2.cleanupParser()
+
+if libxml2.debugMemory(1) == 0:
+    print "OK"
+else:
+    print "Memory leak %d bytes" % (libxml2.debugMemory(1))
+    libxml2.dumpMemory()