Completely disable proxy prefs in Unsafe Browser.

When network.proxy.type=0 and some other network.proxy.* is set in
user.js, Iceweasel behaves weirdly, so we make sure only
network.proxy.type=0 is set.

config/chroot_local-includes/usr/local/sbin/unsafe-browser

@@ -156,7 +156,7 @@ configure_chroot () {
     chroot ${CHROOT} apt-get remove --yes xul-ext-*
 
     # Disable proxying in the chroot
-    sed -i '/^user_pref("network.proxy.type",/d' \
+    sed -i '/^user_pref("network\.proxy\..*",/d' \
         ${CHROOT}/etc/iceweasel/profile/user.js
     echo 'user_pref("network.proxy.type", 0);' >> \
         ${CHROOT}/etc/iceweasel/profile/user.js