Fix memory leak in Python object duplication code.

* subversion/bindings/swig/python/libsvn_swig_py/swigutil_py.c
  (make_ob_txdelta_window, make_ob_log_changed_path,
   make_ob_wc_status, make_ob_lock, make_ob_auth_ssl_server_cert_info,
   make_ob_info, make_ob_location_segment, make_ob_commit_info,
   make_ob_wc_notify): Fix memory leak.

Index: swigutil_py.c
===================================================================
--- swigutil_py.c	(revision 28528)
+++ swigutil_py.c	(working copy)
@@ -780,8 +780,10 @@
   PyObject *new_py_pool = svn_swig_NewPointerObj(new_pool, \
     svn_swig_TypeQuery("apr_pool_t *"), application_py_pool, NULL); \
   svn_##type##_t *new_value = dup(value, new_pool); \
-  return svn_swig_NewPointerObjString(new_value, "svn_" #type "_t *", \
-      new_py_pool); \
+  PyObject *obj = svn_swig_NewPointerObjString(new_value, "svn_" #type "_t *", \
+                                               new_py_pool); \
+  Py_XDECREF(new_py_pool); \
+  return obj; \
 }
 
 DECLARE_SWIG_CONSTRUCTOR(txdelta_window, svn_txdelta_window_dup)