FAIL_OVER: Fix warning value computed is not used
src/providers/fail_over.c: In function ‘fo_ref_server’:
src/providers/fail_over.c:861: warning: value computed is not used
Reviewed-by: Jakub Hrozek <jhrozek@redhat.com>
(cherry picked from commit acd615cffd144b69e2558a0fc45c6966423f2d02)