Bug 766: Use the new plugin to generate sort dropdown list - memberentry

Bug 766: Use the new plugin to generate sort dropdown list - memberentry

Now we can use the method plugin from the memberentry form.

Test plan:
1/ Create a patron and verify sort1 and sort2 dropdown list are
   correctly generated.
2/ Select values.
3/ Save.
4/ Edit the patron and verify the selected values are displayed.

Signed-off-by: Bernardo Gonzalez Kriegel <bgkriegel@gmail.com>
Works as described.

Signed-off-by: Katrin Fischer <Katrin.Fischer.83@web.de>
Signed-off-by: Galen Charlton <gmc@esilibrary.com>