Fixing seed_likelihood mass model change for offline ranks

Currently, the workflow adds an explicit option --old-mass-model-file for create_prior_diststats because the add_ranking_stat_file_options doesn't add that option as a suppressed option. This is not a problem for online ranks, because they call the create_prior_seed layer instead of create_prior, and apparently it overwrites that option with a suppressed one here

Since this has now been fixed directly in the add_ranking_stat_file_options, maybe we can remove the explicit re-setting of the option in the create_prior_seed layer?

Additionally, since we've now gotten into the habit of setting an absolute path for the mass model instead of a relative one, do we even need to transfer in the mass model? For absolute paths, I think it's going to take the mass model directly from the shared file system, instead of the transferred-in mass model. Note that this might be over-burdening the shared file system