userportal, webadmin: run favicon bug workaround in Scheduler

Run the Firefox favicon bug workaround in GWT Scheduler, since GWT-P
place transition implementation uses deferred commands.

Change-Id: I73278382894d02970022ceef8b95d8c2f3b62ec0
Bug-Url: https://bugzilla.redhat.com/999436
Signed-off-by: Greg Sheremeta <gshereme@redhat.com>