Fixed a memory leak that was introduced with incorrect usage of the Python weak

reference API in pysqlite 2.2.1.

Bumbed pysqlite version number to upcoming pysqlite 2.3.1 release.

Modules/_sqlite/connection.c

@@ -664,7 +664,7 @@ void _drop_unused_statement_references(Connection* self)
 
     for (i = 0; i < PyList_Size(self->statements); i++) {
         weakref = PyList_GetItem(self->statements, i);
-        if (weakref != Py_None) {
+        if (PyWeakref_GetObject(weakref) != Py_None) {
             if (PyList_Append(new_list, weakref) != 0) {
                 Py_DECREF(new_list);
                 return;

Modules/_sqlite/module.h

@@ -25,7 +25,7 @@
 #define PYSQLITE_MODULE_H
 #include "Python.h"
 
-#define PYSQLITE_VERSION "2.3.0"
+#define PYSQLITE_VERSION "2.3.1"
 
 extern PyObject* Error;
 extern PyObject* Warning;