Sanitize path also for regular ones

Otherwise I'll get this error (if the path is a `regular` instead of `symlink` one):

```elixir
==> Generating boot script...
==> Generating release...
error (enotdir) accessing file /home/chris/.exenv/versions/0.13.0.dev/bin/elixir/lib

==> Failed to build release. Please fix any errors and try again.
```

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(+ whitespace removal, newline at EOL)