LU-1247 obdfilter: fix invalid check of precrate objects

LU-1247 obdfilter: fix invalid check of precrate objects

MDT precreate objects when it has objects count less than the
oscc->oscc_grow_count / 2. oscc->oscc_grow_count can be equal
to OST_MAX_PRECREATE, so MDT (last_id - next_id) is less than the
(OST_MAX_PRECREAT * 3 / 2). This patch fix the wrong condition at
filter_handle_precreate() when delete orphans request happend.

Signed-off-by: Alexander Boyko <alexander_boyko@xyratex.com>
Reviewed-by: Andrew Perepechko <andrew_perepechko@xyratex.com>
Reviewed-by: Andriy Skulysh <andriy_skulysh@xyratex.com>
Xyratex-bug-id: MRP-440
Change-Id: I5bac3ee7261fe7462254bd80565d770041c3c206
Reviewed-on: http://review.whamcloud.com/2365
Reviewed-by: Andriy Skulysh <Andriy_Skulysh@xyratex.com>
Tested-by: Hudson
Tested-by: Maloo <whamcloud.maloo@gmail.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>