In THcParmList::Load only look for run ranges in top file.

  Previously, if load was called with a run number, array continuation
  lines in included files were being interpreted as lists of run numbers.
  Still we have the limitation that in the top file, if we define an array
  with multiple lines, the continuation lines will be interpreted as
  run number lists and mess things up.  But it is unlikely that we would
  need to define arrays in the top file when we are in run number
  mode.