Fix multi-rank debug case problem (MFlowCode#696)

Author: sbryngelson

src/pre_process/m_mpi_proxy.fpp

@@ -43,7 +43,7 @@ contains
         ! Logistics
         call MPI_BCAST(case_dir, len(case_dir), MPI_CHARACTER, 0, MPI_COMM_WORLD, ierr)
 
-        #:for VAR in ['t_step_old', 'm', 'n', 'p', 'm_glb', 'n_glb', 'p_glb',  &
+        #:for VAR in ['t_step_old', 't_step_start', 'm', 'n', 'p', 'm_glb', 'n_glb', 'p_glb',  &
             & 'loops_x', 'loops_y', 'loops_z', 'model_eqns', 'num_fluids',     &
             & 'weno_order', 'precision', 'perturb_flow_fluid', &
             & 'perturb_sph_fluid', 'num_patches', 'thermal', 'nb', 'dist_type',&