This PR relates to #3026.
In order to avoid an exception, Value has to be replaced with FloatValue in two places.
Apart from that, missing modules were included in two places.
The (use-modules (opencog persist)) is actually wrong; in that case the (cog-delete!) at the end needed to be changed to (cog-extract!) ... I'm fixing that now.
This PR relates to #3026.
In order to avoid an exception, Value has to be replaced with FloatValue in two places.
Apart from that, missing modules were included in two places.