ReplicatedPG: don't crash on empty data_subset in sub_op_push
ReplicatedPG: don't crash on empty data_subset in sub_op_push

If data_subset is empty (i.e., the data we pulled is no longer useful),
we should mark complete false and continue rather than fail the
assert in range_end().

Signed-off-by: Samuel Just <4c46b94684b338bae1ed5e7e1321718dd75401cc@dreamhost.com>

ajnelson/ceph,ajnelson/ceph,ajnelson/ceph,ajnelson/ceph,ajnelson/ceph,ajnelson/ceph