Temporary fix to disallow stars as regular stop/city names

SLU will now sometimes produce outputs such as 'inform(from_stop="*")',
where the value has no meaning (we only know the user mentioned the
slot). However, it was still interpreted as an ordinary value, leading
to weird prompts such as:

    OK, from the stop *.

This fix makes HDC policy ignore all "*" values.

However, "*" still stays in dialogue tracking. A permanent fix should
probably interpret it somehow.
Just removing a weird unneeded line (no idea where it came from)
Merge pull request #98 from UFAL-DSG/fix_stars

Fix for star slot values sifting through to the output