Rhaas/unused vars

• Hydro_RNSID: use CCTK_VERROR to report errors

• Hydro_RNSID: remove unused variables

• Hydro_RNSID: move strcmp out of loops

  this was an attempt to remove compiler warnings about unset vars, but the compiler is not clever enough to track the deps in:

  int var, othervar; const int cond = strcmp(s, "");

  if(cond) var = 42;

  if(cond) othervar = var;

• Hydro_RNSID: use do..while to get rid of compiler warnings

  this also fixes a bug if anyone ever asks for an accuracy of worse than 1.0

• Hydro_RNSID: pacify compiler about Omega_c maybe being unset

• Hydro_RNSID: do not output parfile, fileinfo or run speed in tests

  these quantities cannot be compared between machines

The only change that should merit actual review is the do..while change