Remove magic-trace v15
Remove magic-trace v15

That version is impossibly out of date. Anyone who uses it should
instead use magic-trace 1.0.0.

Normally, I wouldn't yank this. If only for the historically curious.
But, per the discussion at #21227, it's causing issues for people
because opam sorts v15 as > 1.0.0.

djs55/opam-repository,fpottier/opam-repository,emillon/opam-repository,fpottier/opam-repository,pqwy/opam-repository,hannesm/opam-repository,astrada/opam-repository,emillon/opam-repository,astrada/opam-repository,pqwy/opam-repository,djs55/opam-repository,hannesm/opam-repository,kkirstein/opam-repository,Leonidas-from-XIV/opam-repository,jhwoodyatt/opam-repository,pirbo/opam-repository,jhwoodyatt/opam-repository,codinuum/opam-repository,codinuum/opam-repository,pirbo/opam-repository,nberth/opam-repository,ocaml/opam-repository,kkirstein/opam-repository,ocaml/opam-repository,Leonidas-from-XIV/opam-repository,nberth/opam-repository