r.drain: ignore values option if raster values are not used (no -c or -a flag)

git-svn-id: https://svn.osgeo.org/grass/grass/trunk@73009 15284696-431f-4ddb-bdfa-cd5b030d7da7

scripts/r.drain/r.drain.py

@@ -147,7 +147,8 @@ def main():
     # create args for r.path
     kwargs = {}
     kwargs['input'] = dirmap
-    kwargs['values'] = valmap
+    if flags['c'] or flags['a']:
+        kwargs['values'] = valmap
     kwargs['format'] = 'degree'
     if start_coords:
         kwargs['start_coordinates'] = start_coords