Fix ransac random generator seeding

Ransac's get_rand_indices originally used rand_r seeded with the
same value every time, producing the same random sequence at every
iteration. This causes the global motion parameters to be slightly
less accurate because ransac cannot improve the model fit after
the first attempt.

Change-Id: Idca2f88468ea21d19ba41ab66e5a2744ee33aade
1 file changed