Free the correct type in OBJ_add_object()

We should be using ASN1_OBJECT_free() not OPENSSL_free().

Fixes #5568
Reviewed-by: NRich Salz <rsalz@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/5597)

crypto/objects/obj_dat.c

@@ -213,7 +213,7 @@ int OBJ_add_object(const ASN1_OBJECT *obj)
  err:
     for (i = ADDED_DATA; i <= ADDED_NID; i++)
         OPENSSL_free(ao[i]);
-    OPENSSL_free(o);
+    ASN1_OBJECT_free(o);
     return NID_undef;
 }