Update file-system references from /w/static to /static
URL references to /w/static never really existed (it was always symlinked from
docroots as "/static"), but before I47eac0498 it was the main location on-disk.
- File pointers in wmf-config
- Symlinks in docroot.
TODO: symlinks in (unused) /images directory. Maybe leave those for now
and remove at the sime time we remove (unused) /w/static.