osgeo4w: default internet browser of the system is invoked

git-svn-id: https://svn.osgeo.org/grass/grass/trunk@45557 15284696-431f-4ddb-bdfa-cd5b030d7da7

mswindows/osgeo4w/env.bat.tmpl

@@ -4,5 +4,5 @@ set GRASS_SH=%OSGEO4W_ROOT%\apps\msys\bin\sh.exe
 set GRASS_WISH=%OSGEO4W_ROOT%\bin\wish.exe
 set GRASS_PYTHON=%OSGEO4W_ROOT%\bin\python.exe
 set GRASS_PROJSHARE=%OSGEO4W_ROOT%\share\proj
-set GRASS_HTML_BROWSER=%PROGRAMFILES%\Internet Explorer\iexplore.exe
+set GRASS_HTML_BROWSER=explorer
 set PATH=%OSGEO4W_ROOT%\apps\grass\grass-@VERSION@\bin;%PATH%