ql:*local-project-directories* is not forwarded in static-image-op's perform

[Pierre Neidhardt]

When a custom directory is added to `ql:*local-project-directories*`, `static-image-op`'s specialization of `perform` fails to forward its value to the SBCL / CLISP subprocess.

This may lead the operation to fail if it relies on a system found in the custom directory.

Indeed, the Quicklisp setup is capture:

```
                        ,@(if-let (ql-home
                                   (symbol-value (find-symbol* '*quicklisp-home* 'ql-setup nil)))
                            `((load ,(subpathname ql-home "setup.lisp"))))
```

but that's it. I believe `ql:*local-project-directories*` should be forwarded after the `load`.