Stop saving patron barcode in cookies

Stop saving patron barcode in cookies

This causes bad interactions between patron windows and normal catalog
windows. Examples:

Load a patron, load place hold catalog in patron window. Future loads of
non-patron catalogs will default to this patron.

Load Patron A from written note, and open Place Hold catalog. Start
searching for the item Patron A wants.
Get interupted by Patron B calling. Load Patron B, and open Place Hold
catalog. Search, place a hold for Patron B.
Return to Patron A, find item, go to place hold. Find Patron B's barcode
populated.

Instead, teach the staff javascript, that already knows how to load hold
preferences, how to grab the barcode from xulG. This barcode should be
specific to the patron window the catalog is embedded in, and won't 'leak'
to other catalog interfaces.

Signed-off-by: Thomas Berezansky <tsbere@mvlc.org>