[support] manually disable custom block

[Jason White]

OK ... I've managed to implement a custom block that hoses my login  
block (amazing what happens when you forget to close your form  
tag! ... <smacks self over head>.  I need to disable it from the back  
end.  I'm looking at the blocks table, but don't see a way. Any one  
have an idea on this one? And of course I'm supposed to orient a few  
people to putting content into the system in a little bit .. .ugggh!

TIA,

Jason