wxGUI/nviz: fix coloring isosurfaces, broken in https://trac.osgeo.org/grass/changeset/64301 (merge from trunk, https://trac.osgeo.org/grass/changeset/66588)

git-svn-id: https://svn.osgeo.org/grass/grass/branches/releasebranch_7_0@66589 15284696-431f-4ddb-bdfa-cd5b030d7da7

gui/wxpython/nviz/mapwindow.py

@@ -2035,7 +2035,7 @@ class GLWindow(MapWindowBase, glcanvas.GLCanvas):
                             continue
                         if map and not grass.find_file(value, element='grid3')['fullname']:
                             continue
-                    elif attrb ==  'color':
+                    if attrb ==  'color':
                         self._display.SetIsosurfaceColor(id, isosurfId, map, str(value))
                     elif attrb ==  'mask':
                         # TODO: invert mask