opam: remove unnecessary dependency on ocamlfind
opam: remove unnecessary dependency on ocamlfind

The jbuilder tool parses ocamlfind META files but does not use the library
or the utility itself.

Signed-off-by: David Scott <63c9eb0ea83039690fefa11afe17873ba8278a56@docker.com>

djs55/vpnkit,djs55/vpnkit,djs55/vpnkit