message: remove zeroing kin_pp
  When connecting as SUNLinearSolver the initial guess is zeroed out
  before calling the solve routine so this is not needed any more.
diff: @@ -936,15 +936,6 @@ namespace mfem
  flag = KINInit(sundials_mem, KINSolver::Mult, y);
  MFEM_VERIFY(flag == KIN_SUCCESS, "error in KINInit()");
  - // <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<
  - // CHECK THIS
  - // Initialization of kin_pp; otherwise, for a custom Jacobian inversion,
  - // the first time we enter the linear solve, we will get uninitialized
  - // initial guess (matters when iterative_mode = true).
  - // N_VConst(ZERO, mem->kin_pp);
  - // CHECK THIS
  - // >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
  -
  // Attach the KINSolver as user-defined data
  flag = KINSetUserData(sundials_mem, this);
  MFEM_ASSERT(flag == KIN_SUCCESS, "error in KINSetUserData()");
  