r.fill.dir use standardized options (https://trac.osgeo.org/grass/ticket/2409)

git-svn-id: https://svn.osgeo.org/grass/grass/trunk@63005 15284696-431f-4ddb-bdfa-cd5b030d7da7

raster/r.fill.dir/main.c

@@ -96,7 +96,7 @@ int main(int argc, char **argv)
     opt2->description = _("Name for output depressionless elevation raster map");
     
     opt4 = G_define_standard_option(G_OPT_R_OUTPUT);
-    opt4->key = "outdir";
+    opt4->key = "direction";
     opt4->description = _("Name for output flow direction map for depressionless elevation raster map");
 
     opt5 = G_define_standard_option(G_OPT_R_OUTPUT);