FUEL: Fix bug in usings update doing the wrong thing for empty USING:.
FUEL: Fix bug in usings update doing the wrong thing for empty USING:.

nicolas-p/factor,seckar/factor,bpollack/factor,erg/factor,factor/factor,cataska/factor,sarvex/factor-lang,bjourne/factor,kingcons/factor,sarvex/factor-lang,bjourne/factor,factor/factor,dch/factor,slavapestov/factor,tgunr/factor,dch/factor,slavapestov/factor,sarvex/factor-lang,AlexIljin/factor,AlexIljin/factor,AlexIljin/factor,mrjbq7/factor,erg/factor,bpollack/factor,Keyholder/factor,dch/factor,mrjbq7/factor,AlexIljin/factor,cataska/factor,mcandre/factor,erg/factor,nicolas-p/factor,tgunr/factor,tgunr/factor,mcandre/factor,AlexIljin/factor,ceninan/factor,bjourne/factor,sarvex/factor-lang,nicolas-p/factor,bjourne/factor,slavapestov/factor,Keyholder/factor,kingcons/factor,erg/factor,sarvex/factor-lang,bpollack/factor,ehird/factor,slavapestov/factor,jwmerrill/factor,bjourne/factor,Keyholder/factor,dharmatech/factor,ehird/factor,factor/factor,mcandre/factor,littledan/Factor,slavapestov/factor,mcandre/factor,tgunr/factor,bpollack/factor,dharmatech/factor,nicolas-p/factor,nicolas-p/factor,AlexIljin/factor,tgunr/factor,nicolas-p/factor,kingcons/factor,seckar/factor,bpollack/factor,mcandre/factor,AlexIljin/factor,bpollack/factor,erg/factor,bjourne/factor,sarvex/factor-lang,mrjbq7/factor,sarvex/factor-lang,ehird/factor,nicolas-p/factor,ceninan/factor,erg/factor,factor/factor,dch/factor,littledan/Factor,slavapestov/factor,slavapestov/factor,littledan/Factor,erg/factor,cataska/factor,jwmerrill/factor,seckar/factor,bjourne/factor,ceninan/factor,factor/factor,mcandre/factor,bpollack/factor,kingcons/factor,mrjbq7/factor,cataska/factor,ceninan/factor,factor/factor,dharmatech/factor,mrjbq7/factor,dch/factor,mrjbq7/factor,littledan/Factor,tgunr/factor,mcandre/factor,jwmerrill/factor,dch/factor