acprep: remove dead code

This isn't used anywhere since 4681e58d7f3cda2a2ac6d05b6ec1a106f568e029.
Merge pull request #300 from jacknagel/patch-2

acprep: remove dead code
Don't lose commodity when cost is not separated by whitespace

When a cost was specified without a whitespace after the @ symbol,
as in @$5.01, this was incorrectly parsed as 5.01 (losing the
commodity) rather than $5.01.

Bug fix for #1050