LU-397 Set 'lsr_flags' as 'LU_SEQ_RANGE_MDT' for old 2.0 client

LU-397 Set 'lsr_flags' as 'LU_SEQ_RANGE_MDT' for old 2.0 client

Lustre 2.x introduces server identifier into lu_seq_range to distinguish
MDT and OST fids. But for old 2.0 client, it does not specify such
identifier/flags. So use 'OBD_CONNECT_SEQ_RANGE' to distinguish whether
it is old 2.0 client or not. For old 2.0 client, set the 'lsr_flags' as
'LU_SEQ_RANGE_MDT' by default.

Change-Id: I652caa637959268e1da499370a0efd356ff98bbe
Signed-off-by: nasf <yong.fan@whamcloud.com>
Reviewed-on: http://review.whamcloud.com/902
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Tested-by: Hudson
Reviewed-by: Oleg Drokin <green@whamcloud.com>