CDRIVER-5834 Do not compare uninitialized bytes in _mongoc_server_description_equal (#1814)

Fix possible comparison of uninitialized bytes in `bson_error_t`.

---------

Co-authored-by: Ezra Chung <[email protected]>

Author: 2 people

src/libmongoc/src/mongoc/mongoc-server-description.c

@@ -1151,7 +1151,8 @@ _mongoc_server_description_equal (mongoc_server_description_t *sd1, mongoc_serve
       return false;
    }
 
-   if (0 != memcmp (&sd1->error, &sd2->error, sizeof (bson_error_t))) {
+   if (sd1->error.domain != sd2->error.domain || sd1->error.code != sd2->error.code ||
+       0 != strncmp (sd1->error.message, sd2->error.message, BSON_ERROR_BUFFER_SIZE)) {
       return false;
    }