intro-install_plan: fix destinations for build_targets with custom install_dir

There are a couple issues that combine to make the current handling a
bit confusing.

- we call it "install_dir_name" but it is only ever the class default

- CustomTarget always has it set to None, and then we check if it is
  None then create a different variable with a safe fallback. The if is
  useless -- it cannot fail, but if it did we'd get an undefined
  variable error when we tried to use `dir_name`

Remove the special handling for CustomTarget. Instead, just always
accept None as a possible value of outdir_name when constructing install
data, and, if it is None, fall back to {prefix}/outdir regardless of
what type it used to be.

0 files changed, 0 insertions, 0 deletions