I did not see anything about dropping the black Superman but there were rumors that the studio really liked the script but felt there was too little action which might hurt the project's financial viability, so they sent to script back for some rewrites. As far as we know the project is in pre-production but there have been no recent updates.
Heard a podcast where they asked if audiences won't turn out for a Superman film why would they think they would for a black Superman film with big changes to core elements of the character? There is financial risk with the project even with a good script. I am not convinced WB will go forward with it.