I think the &optional package-status-alist argument isn't needed

I noticed `el-get-merge-properties-into-status` had this `&optional package-status-alist` which was never actually used, except for the call in `el-get-do-init` which was only passing *its* `&optional package-status-alist`, and so on... There seems to be a whole bunch of functions with this optional argument that is never actually used anywhere. After removing them all, I get no compile errors/warnings about it, so I think this is safe.

```
* el-get-status.el (el-get-package-status-alist,
el-get-package-status-recipes, el-get-read-package-status,
el-get-read-package-status-recipe, el-get-with-status-sources,
el-get-read-cached-recipe, el-get-merge-properties-into-status):
* el-get.el (el-get-init, el-get-do-init, el-get-reload, el-get-remove,
el-get-checksum): Remove &optional package-status-alist argument.
```