LU-16057 obdclass: set OBD_MD_FLGROUP for ladvise RPC

LU-16057 obdclass: set OBD_MD_FLGROUP for ladvise RPC

ladvise RPC doesn't have OBD_MD_FLGROUP set, when RPC
reaches server, tgt_validate_obdo() will corrupt the FID
if it's seq is in FID_SEQ_NORMAL range.

Do not mess with seq in obdo_to_ioobj() and tgt_validate_obdo(),
since 2.0 all RPCs should have OBD_MD_FLGROUP set.

Add OBD_MD_FLGROUP for ladvise RPC to fix new client talking
to old servers.

Change-Id: I373b7f32458b18e29d9bb716a912fe4a54eccac5
Signed-off-by: Li Dongyang <dongyangli@ddn.com>
Reviewed-on: https://review.whamcloud.com/48080
Tested-by: jenkins <devops@whamcloud.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Arshad Hussain <arshad.hussain@aeoncomputing.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>