Redirecting to wp-admin/install.php althought it is already installed

Hello everybody,
I migrated WP installation from localhost to test server. I did already so many times before:
1) Export from old DB server, import to a new one
2) Change siteurl and home in wp_options table
3) Change DB settings if any in wp-config.php

But this time, WP is incorrectly responding HTTP 302 Moved Temporarily and redirecting to /wp-admin/install.php to start fresh install but I do have already WP installed.

I did try to study source code with without any success. Do anybody have some suggestments what went wrong in my case?

Thanks Libor