LU-14911 osp: release thandle if it was created

LU-14911 osp: release thandle if it was created

osp_statfs_update() could leak thandle if transaction couldn't
start for a reason.

Signed-off-by: Alex Zhuravlev <bzzz@whamcloud.com>
Change-Id: I541a5e4a7860008eb179d905ac57997b737f178c
Reviewed-on: https://review.whamcloud.com/44504
Reviewed-by: Mike Pershin <mpershin@whamcloud.com>
Reviewed-by: Lai Siyao <lai.siyao@whamcloud.com>
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>