free NULL cleanup

This commit handles BIO_ACCEPT_free BIO_CB_FREE BIO_CONNECT_free
BIO_free BIO_free_all BIO_vfree

Reviewed-by: Matt Caswell <matt@openssl.org>

apps/ocsp.c

@@ -1362,8 +1362,7 @@ OCSP_RESPONSE *process_responder(BIO *err, OCSP_REQUEST *req,
     if (!resp)
         BIO_printf(bio_err, "Error querying OCSP responder\n");
  end:
-    if (cbio)
-        BIO_free_all(cbio);
+    BIO_free_all(cbio);
     if (ctx)
         SSL_CTX_free(ctx);
     return resp;