LU-10070 lod: SEL cleanup

LU-10070 lod: SEL cleanup

some cleanups
- dt_statfs with an extra paremeter to be dt_statfs_info;
- lod_statfs_and_check does not need an extra parameter and
to be static again;
- move asserts to a better place;
- test component-add with wrong paremeters;
- print out the layout sanity errors wherever needed;
- make an array of layout_sanity errors;
- an HSM sanity test is added;

and one defect:
- the last component cannot be 0-lenght;

Signed-off-by: Vitaly Fertman <c17818@cray.com>
Change-Id: If832579ce27cb6ab87d36a594c04363deaea8711
Reviewed-on: https://review.whamcloud.com/35414
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Alexey Lyashkov <c17817@cray.com>
Reviewed-by: Patrick Farrell <pfarrell@whamcloud.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>