Vandelay: repair item attr context org selector

Vandelay: repair item attr context org selector

1. Prevents resetting the context selector to the workstation org unit
each time it's changed.

2. Prevent the unintentional pileup of dojo.connect() events, which
can lead to exponential growth in the number of server calls to fetch
import-item-attribute-definitions with each change of the context org
selector.

Signed-off-by: Bill Erickson <berick@esilibrary.com>