Come to think about it, I think it would be better if we were to 
incorporate the X86_BUG_NULL_SEG null segment load in into the main 
native_load_gs_index() code while we are swapgs'd anyway. This 
simplifies the code further, and should avoid calling 
native_load_gs_index() twice if this bug is enabled.

(This is the traps.c code only; removing the now unnecessary instances 
is left as an exercise for the reader...)

	-hpa