staging: lustre: lnet: memory corruption in selftest

We want sizeof(struct lstcon_node) but instead we're getting the sizeof
a pointer.

Fixes: 8d78f0f2 ("staging: lustre: lnet: cleanup some of the > 80 line issues")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>