LU-6828 lod: fix memory leak in lod_connect_to_osd

LU-6828 lod: fix memory leak in lod_connect_to_osd

We would replace '$fsname-mdtlov' to '$fsname-MDT0000-osd'
when upgrade from 1.x. But buffer alloced as former length.

Signed-off-by: Yang Sheng <yang.sheng@intel.com>
Change-Id: I8c92e3cb4472527fa5ad5da7f0e4cb498eaccb6c
Reviewed-on: http://review.whamcloud.com/15635
Tested-by: Jenkins
Reviewed-by: Bobi Jam <bobijam@hotmail.com>
Reviewed-by: Alex Zhuravlev <alexey.zhuravlev@intel.com>
Reviewed-by: Fan Yong <fan.yong@intel.com>
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>