Bug #39403 Setup a redirect from /merlin to /

Description:
In MEM 2.0, the base application directory was moved from /merlin to /.  For example, in older versions, you would go to:

http://localhost:18080/merlin

In 2.0 you would instead go to:

http://localhost:18080/

The /merlin URL in 2.0 gives a 404 error.  This causes all bookmarks from older versions to stop working.  Instead, /merlin should redirect to /.

The old / page used to recommend bookmarking /merlin, so we should support /merlin for backwards compatibility purposes.

In addition, my browser cached / which used the old redirect to /merlin, so when I tried to launch it normally, I would be redirected to a 404.  Clearing my browser cache fixed this, just took me a while to figure out what was going on.

How to repeat:
Install 1.3 and bookmark the main page.
Install 2.0 and try to visit bookmark.
Get 404 error.

Suggested fix:
Make /merlin redirect to /

Note: in 1.3 we added an html redirect

revno: 6304.1.1
    revision-id: jsled@asynchronous.org-20081002192541-oganyu04vmgoyhe7
    parent: sloan@mysql.com-20081002182419-aosradl3bzgbkvt0
    committer: Josh Sled <jsled@asynchronous.org>
    branch nick: local
    timestamp: Thu 2008-10-02 15:25:41 -0400
    message:
      Bug#39403: redirect /merlin/ -> /; remove previous /merlin/{rest,heartbeat} proxies

we now have redirects from '/merlin/' to '/'.  Previous special-cases for </merlin/rest> and </merlin/inventory> will now be redirected (http 301 "moved permenantly").  In case agents or other clients don't handle redirects, we should ensure the upgrade installer and documentation just refer to </> instead of </merlin/>.

Also note:

    revno: 6277.1.48
    revision-id: jsled@asynchronous.org-20081006185505-a88ueewoz7rm4kbx
    parent: bill@alien8-20081006181320-6hymh399q0oazf8o
    committer: Josh Sled <jsled@asynchronous.org>
    branch nick: local
    timestamp: Mon 2008-10-06 14:55:05 -0400
    message:
      More /merlin/{,inventory} redirection work: if the request is /merlin/inventory, then "forward" the request to the servlet named "rest".  Otherwise, redirect.

Turns out the 301s weren't going to work with fielded blackout-API-using scripts.  So, we now do something a bit more complicated. :/

Verified fixed in build 2.0.0.7075.

A note has been added to the 2.0.0. changelog: 

The base application directory for the &merlin_client; has been updated from <literal>http://localhost:18080/merlin</literal> to <literal>http://localhost:18080/</literal>.