[2.1.x] Removed "encoding" description in GIS tutorial.

An omission in 388165ad.
Backport of 3deea61f from master

docs/ref/contrib/gis/tutorial.txt

@@ -474,9 +474,6 @@ A few notes about what's going on:
   the script will still work.
 * The ``transform`` keyword is set to ``False`` because the data in the
   shapefile does not need to be converted -- it's already in WGS84 (SRID=4326).
-* The ``encoding`` keyword is set to the character encoding of the string
-  values in the shapefile. This ensures that string values are read and saved
-  correctly from their original encoding system.
 
 Afterwards, invoke the Django shell from the ``geodjango`` project directory: