ledger: 3.0.2 -> 3.0.4
boost: Quick eval fix
Remove references to <nixpkgs>

Nixpkgs should not use <nixpkgs> to refer to itself, because $NIX_PATH
might not be set or not point to the same Nixpkgs. It's also
unnecessary.
boost155: specify lib dir for lib output
Revert "boost155: specify lib dir for lib output"

This reverts commit e640935da6052547faaa8fe7d63bd8774de9f45c.