Fix: unit output (use_short_label)

[Humml87]

Now the same short Labels are used.

P.S. in transiflex no resources exist for ....Short, which is generated from 'measuringUnitString'.

[eldy]

We use the param 1 because we are in a table where we must save spaces, so we ask to use the very short label. So for "piece", we should get "p".
this is strange, old code
$unitforline = measuringUnitString($line->fk_unit, '', '', 1);
seems to return correctly "p"
If using 2, we will get PieceShort. So 1 seems the correct value. Did i miss something ?