Christine 28/11/2019: remove unused files, replaced by _n routine for tree drag

src/MNH/modd_dragtree.f90

-!MNH_LIC Copyright 1994-2014 CNRS, Meteo-France and Universite Paul Sabatier
-!MNH_LIC This is part of the Meso-NH software governed by the CeCILL-C licence
-!MNH_LIC version 1. See LICENSE, CeCILL-C_V1-en.txt and CeCILL-C_V1-fr.txt  
-!MNH_LIC for details. version 1.
-!!
-!!    #####################
-      MODULE MODD_DRAGTREE
-!!    #####################
-!!
-!!*** *MODD_DRAGTREE*
-!!
-!!    PURPOSE
-!!    -------
-!       Declaration to take into account tree drag in Meso-NH              
-!              instead of SURFEX. 
-!!
-!!**  AUTHOR
-!!    ------
-!!    C.Lac                   *CNRM*
-!
-!!    MODIFICATIONS
-!!    -------------
-!!    Original 30/06/11
-!!    06/16  (C.Lac) Add droplet deposition
-!-----------------------------------------------------------------------------
-!
-!*       0.   DECLARATIONS
-!        -----------------
-IMPLICIT NONE
-LOGICAL    ::     LDRAGTREE    ! flag used to  take into account tree drag in 
-!                              ! the atmospheric model instead of SURFEX.
-LOGICAL    ::     LDEPOTREE    ! flag for droplet deposition on trees
-!
-REAL       ::     XVDEPOTREE   ! Droplet deposition velocity
-!
-END MODULE MODD_DRAGTREE

src/MNH/modn_dragtree.f90

-!MNH_LIC Copyright 1994-2014 CNRS, Meteo-France and Universite Paul Sabatier
-!MNH_LIC This is part of the Meso-NH software governed by the CeCILL-C licence
-!MNH_LIC version 1. See LICENSE, CeCILL-C_V1-en.txt and CeCILL-C_V1-fr.txt  
-!MNH_LIC for details. version 1.
-!!
-!!    #####################
-      MODULE MODN_DRAGTREE
-!!    #####################
-!!
-!!*** *MODN_DRAGTREE*
-!!
-!!    PURPOSE
-!!    -------
-!       Namelist to take into account tree drag in the atmospheric model
-!              instead of SURFEX. 
-!!
-!!**  AUTHOR
-!!    ------
-!!    C.Lac                   *CNRM*
-!
-!!    MODIFICATIONS
-!!    -------------
-!!    Original 30/06/11
-!!
-!!    10/2016 : (C.Lac) Add droplet deposition on trees
-!!    IMPLICIT ARGUMENTS
-!!    ------------------
-USE MODD_DRAGTREE                           
-!!
-!-----------------------------------------------------------------------------
-!
-!*       0.   DECLARATIONS
-!        -----------------
-IMPLICIT NONE
-SAVE
-NAMELIST /NAM_DRAGTREE/  &
-     LDRAGTREE,LDEPOTREE,XVDEPOTREE                        
-
-!
-END MODULE MODN_DRAGTREE