OSGeo4W BAT files review (#437)

* clean-up bat files

* PROJ_LIB already defined by etc/ini/proj.bat

* GDAL_DATA already defined by etc/ini/gdal.bat

* GEOTIFF_CSV already defined by etc/ini/libgeotiff.bat

mswindows/osgeo4w/env.bat.tmpl

@@ -11,19 +11,14 @@ REM Note that msys package must be also installed
 REM set GRASS_SH=%OSGEO4W_ROOT%\apps\msys\bin\sh.exe
 
 set GRASS_PYTHON=%OSGEO4W_ROOT%\bin\python3.exe
-set PYTHONHOME=%OSGEO4W_ROOT%\apps\Python37
-
 set GRASS_PROJSHARE=%OSGEO4W_ROOT%\share\proj
 
-set PROJ_LIB=%OSGEO4W_ROOT%\share\proj
-set GDAL_DATA=%OSGEO4W_ROOT%\share\gdal
-set GEOTIFF_CSV=%OSGEO4W_ROOT%\share\epsg_csv
-
 set FONTCONFIG_FILE=%GISBASE%\etc\fonts.conf
 
+REM
+REM RStudio-related
+REM
 REM set RStudio temporarily to %PATH% if it exists
-
 IF EXIST "%ProgramFiles%\RStudio\bin\rstudio.exe" set PATH=%PATH%;%ProgramFiles%\RStudio\bin
-
 REM set R_USER if %USERPROFILE%\Documents\R\ exists to catch most common cases of private R libraries
 IF EXIST "%USERPROFILE%\Documents\R\" set R_USER=%USERPROFILE%\Documents\

mswindows/osgeo4w/grass.bat.tmpl

@@ -9,7 +9,6 @@ rem
 rem Set environmental variables
 rem
 call "%~dp0\o4w_env.bat"
-call py3_env.bat
 call "%OSGEO4W_ROOT%\apps\grass\grass@POSTFIX@\etc\env.bat"
 @echo off