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/ciphers.c

@@ -227,8 +227,7 @@ int MAIN(int argc, char **argv)
         SSL_CTX_free(ctx);
     if (ssl != NULL)
         SSL_free(ssl);
-    if (STDout != NULL)
-        BIO_free_all(STDout);
+    BIO_free_all(STDout);
     apps_shutdown();
     OPENSSL_EXIT(ret);
 }