staging: lustre: lustre: Off by two in lmv_fid2path()

We want to concatonate join string one, a '/' character, string two and
then a NUL terminator.  The destination buffer holds ori_gf->gf_pathlen
characters.  The strlen() function returns the number of characters not
counting the NUL terminator.  So we should be adding two extra spaces,
one for the foward slash and one for the NUL.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: John L. Hammond <john.hammond@intel.com>
Reviewed-by: frank zago <fzago@cray.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>