LU-14831 osd-ldiskfs: uninited osd_inode_id is used

LU-14831 osd-ldiskfs: uninited osd_inode_id is used

In osd_fid_lookup, the "osd_inode_id" could be used uninitializedly
if the FID doesn't exist in OI, which cause some faked FID/inode
pair to be inserted into OI file and the OI scrub thread could be
triggered repeatedly.

Change-Id: I9100dece9e94d3e590f17fb4498601876aa1edaa
Signed-off-by: Hongchao Zhang <hongchao@whamcloud.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Reviewed-on: https://review.whamcloud.com/44349
Tested-by: jenkins <devops@whamcloud.com>
Reviewed-by: Li Dongyang <dongyangli@ddn.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>