[AGENT++] add row at once

[Evgeny Sabelskiy]

Is it possible to create row and fill columns during one SET request ? using
rowCreateAndGo... I did manage to create and fill row in two steps - add row
by rowStatus and fill required columns on the next step. it seems like what
standard method MibTable::could_ever_be_managed doesn't allow to create rows
if first SET is not READ-CREATE type.

Evgeny