partially reverts 35564079: don't ocamlify the name when generating opam file
partially reverts 35564079: don't ocamlify the name when generating opam file

mirage (in `configure_opam`) passes as `~name` argument:
`String.concat ~sep:"-" ["mirage";"unikernel";Info.name;target]`
(where `Info.name` is already `ocamlify`d).

`Info.opam` does another round of `ocamlify`, which results in the filename
mirage-unikernel-hello-macosx.opam which contains:
`name: "mirage_unikernel_hello_macosx"`
for no good reason, but is a source of confusion.

Drup/Functoria,Drup/Functhulhu