Are we going to use the queue_wait field of struct request_queue 
someday? As of 2.6.0-test2, I don't see any use of it. If it's not 
needed anymore, the following patch gets rid of it. Tested this patch by 
compiling for i386 and also doing a grep through all .h and .c files to 
see if it's used somewhere else (admittedly weak).