clean redundant code in Poisson solver

models/PoissonSolver.cpp

@@ -98,9 +98,7 @@ void ScaLBL_Poisson::ReadParams(string filename){
 		h = domain_db->getScalar<double>( "voxel_length" );
 	}
 
-
     //Re-calcualte model parameters if user updates input
-    epsilon0_LB = epsilon0*(h*1.0e-6);//unit:[C/(V*lu)]
     epsilon_LB = epsilon0_LB*epsilonR;//electric permittivity 
 
 	if (rank==0) printf("***********************************************************************************\n");