folder_branch_ops: move rename deCache logic to the notifyOneOp
folder_branch_ops: move rename deCache logic to the notifyOneOp

This way, it will be executed on an inverted notification, as well as
a local rename.

(Note that merging of remote operations while there are outstanding
writes are not currently allowed).

Issue: KBFS-464

keybase/client,keybase/client,keybase/client,keybase/kbfs,keybase/client,keybase/client,keybase/client,keybase/kbfs,keybase/client,keybase/client,keybase/client,keybase/client,keybase/kbfs,keybase/kbfs,keybase/client,keybase/client