fuse_ops_test: in LocalUpdate test, compare correct block IDs
fuse_ops_test: in LocalUpdate test, compare correct block IDs

After the mkdir, make sure the corresponding BatchChanges() has fired
within FuseOps by scheduling a no-op Lookup() before remembering the
BlockPointer for nodes 1 and 2.

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