Usually, the sessions module encloses all operations performed by
a single call to apply_v2() or apply_v2_strm() in a SAVEPOINT. The
SAVEPOINT is committed if the changeset or patchset is successfully
applied, or rolled back if an error occurs. Specifying this flag
causes the sessions module to omit this savepoint. In this case, if the
caller has an open transaction or savepoint when apply_v2() is called,
it may revert the partially applied changeset by rolling it back.
