LU-9088 osd: use od_is_ost check OST FID

LU-9088 osd: use od_is_ost check OST FID

Because OST FLDB is not created until 2.6, so
if the DNE system is upgraded from 2.5 to >=
2.6, then the local FLDB will not be loaded
in fld_index_init(), which might cause OSD
can not tell OST FID created by 2.5. So let's
use od_is_ost in this case.

Change-Id: I5da3e95bc24e43aca1b3c840df427cc5a7306194
Signed-off-by: wangdi <di.wang@intel.com>
Signed-off-by: Bob Glossman <bob.glossman@intel.com>
Reviewed-on: https://review.whamcloud.com/25330
Tested-by: Jenkins
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Minh Diep <minh.diep@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>