'datastore_v3' stub is obtained instead of 'datastore' to clear datastore.
'datastore_v3' stub is obtained instead of 'datastore' to clear datastore.

Under certain circumstances, some entities were not wiped out. testForSequentialValues seems to be fixed because of this change.

rhyolight/nupic.son,rhyolight/nupic.son,rhyolight/nupic.son