Add a lot of missing Py_INCREF
diff --git a/OpenSSL/crypto/pkey.c b/OpenSSL/crypto/pkey.c
index 2591f13..91e446b 100644
--- a/OpenSSL/crypto/pkey.c
+++ b/OpenSSL/crypto/pkey.c
@@ -258,6 +258,9 @@
         return 0;
     }
 
+    /* PyModule_AddObject steals a reference.
+     */
+    Py_INCREF((PyObject *)&crypto_PKey_Type);
     if (PyModule_AddObject(module, "PKeyType", (PyObject *)&crypto_PKey_Type) != 0) {
         return 0;
     }