LP#1531976: fix bringing up Mesage Center and Triggered Events

LP#1531976: fix bringing up Mesage Center and Triggered Events

This patch fixes a bug in the XUL staff client where
using Other -> Triggered Events from the patron page,
then Other -> Message Center, only brings up the Triggered
Events page in both cases (and vice versa).

This patch works by preventing the deck code from thinking they are
the same page, despite both using the browser wrapper as their base URL.

Signed-off-by: Thomas Berezansky <tsbere@mvlc.org>
Signed-off-by: Chris Sharp <csharp@georgialibraries.org>
Signed-off-by: Galen Charlton <gmc@esilibrary.com>