Add a lot of missing Py_INCREF
diff --git a/OpenSSL/crypto/pkcs7.c b/OpenSSL/crypto/pkcs7.c
index fff95e2..a2958d3 100644
--- a/OpenSSL/crypto/pkcs7.c
+++ b/OpenSSL/crypto/pkcs7.c
@@ -203,6 +203,9 @@
         return 0;
     }
 
+    /* PyModule_AddObject steals a reference.
+     */
+    Py_INCREF((PyObject *)&crypto_PKCS7_Type);
     if (PyModule_AddObject(module, "PKCS7Type", (PyObject *)&crypto_PKCS7_Type) != 0) {
         return 0;
     }