Avoid nan in HH variables if MMC not computed
Follow up to !613 (merged)
Could get nan for bbtt_HH_m if the selections are passed but bbtt_mmc_m is not computed. Now stores -99 as other default.
Follow up to !613 (merged)
Could get nan for bbtt_HH_m if the selections are passed but bbtt_mmc_m is not computed. Now stores -99 as other default.