OVN deprecated the datapath_group column from Load_Balancer table. Now
this column was split in two: ls_datapath_group and lr_datapath_group.
This patch changes the code to also look for the datapath group in these
new columns.
This change is backward compatible and will work with a newer or older
version of OVN.
Change-Id: Ia3a95b77fccaa056aa9169114d102258f015002f
Signed-off-by: Lucas Alvares Gomes <lucasagomes@gmail.com>