Remove obsolete artifacts dir. (#456)
Remove obsolete artifacts dir. (#456)

- This was a leftover from the rename in:
  https://github.com/google/grr/commit/a1479d877617ae8216392933c464c4fd075e3b14
destijl/grr,google/grr,dunkhong/grr,google/grr,pidydx/grr,destijl/grr,dunkhong/grr,google/grr,destijl/grr,destijl/grr,pidydx/grr,pidydx/grr,destijl/grr,dunkhong/grr,google/grr,dunkhong/grr,pidydx/grr,dunkhong/grr,pidydx/grr,dunkhong/grr,destijl/grr,dunkhong/grr,pidydx/grr,pidydx/grr,google/grr,google/grr,google/grr,destijl/grr