DIVINE wrapper: Fix program_files and a corner case with no output.
DIVINE wrapper: Fix program_files and a corner case with no output.

martin-neuhaeusser/benchexec,martin-neuhaeusser/benchexec,sosy-lab/benchexec,dbeyer/benchexec,sosy-lab/benchexec,sosy-lab/benchexec,ultimate-pa/benchexec,sosy-lab/benchexec,ultimate-pa/benchexec,sosy-lab/benchexec,IljaZakharov/benchexec,ultimate-pa/benchexec,dbeyer/benchexec,sosy-lab/benchexec,IljaZakharov/benchexec,ultimate-pa/benchexec,martin-neuhaeusser/benchexec,ultimate-pa/benchexec,IljaZakharov/benchexec,martin-neuhaeusser/benchexec,dbeyer/benchexec,IljaZakharov/benchexec,ultimate-pa/benchexec,dbeyer/benchexec