Turns out this was not a good idea as it would too easy to trigger.
If a saturnin sub-command was called from within itself (or another other
sub-command), the $SATURNIN_CONF_PATH computed earlier would just double,
leading to unwanted behavior of saturnin__conf_find(), which would find
items twice.

The original problem should be adressed another way; the testing case
be covered by either writing tests on a lower level; eg. unit tests
and use saturnin__conf_find() or saturnin__conf() without forking.

Another solution on part of Saturnin could be to introduce different
variable (e.g. SATURNIN_CONF_DIRS) for values computed by launcher
and keep $SATURNIN_CONF_PATH just for user.