Speed improvements

Hey there

We’ve been having some problems with our RT system for quite some time,
after doing some investigating we have found that many of the indexes
currently in the RT schema are not used (by mysql). Read the report for info
on which indexes are useful.
Reported: http://fsck.com/rt2/Ticket/Display.html?id=1782

Also we found a disabled queue with a lot of open tickets, this slowed down
the system a lot (a simple check on Queues.Disabled would have stopped
this). To fix this we updated the open/new tickets in this table to
Reported: http://fsck.com/rt2/Ticket/Display.html?id=1783

I hope this will help some of you with bigger tables.