Description of problem:
This is a confusing issue to describe, but it'll be critical to fix, if not for the next future release of JON, but the one after that.  It will drive users batty.

If a user installs a GWT version of JON/RHQ (say, build x) deletes it to install a new version (say, build x+1), the browser gets confused and always attempts to redirect to the login page -- even though of course the login page does not exist on a not-yet-installed version of JON/RHQ.  

Version-Release number of selected component (if applicable):


How reproducible:
Every time

Steps to Reproduce:
1.  Install a gwt build of RHQ/JON  (build "x")
2.  Login to new instance on example.com:7080 
3.  Shut it down and remove it.
4.  Install a newer version of RHQ/JON 
5.  Attempt to navigate to example.com:7080
  
Actual results:
User is redirected (presumably because of browser cache) to login page. This of course does not exist so user gets an error.  User cannot browse back to the installer page.

Expected results:
User is taken to the installer page.

Additional info:
The workaround, at least for Firefox, is to clear browser cache AND history.  Users will not want to do this.

Chrome is even more difficult, but we're not supporting chrome right now, so not a big deal.  I think fixing it for firefox will fix it for chrome as well.

Users may or may not run into this going from, say JON 2.4 to a future release, but if we don't fix it now, they will most certainly run into it going from whatever the next release is to one that comes after that