Revert 7186664e, which broke the old config API.
Revert 7186664e, which broke the old config API.

This was a performance enhancement only, so should have no other
negative effects.

pllim/astropy,DougBurke/astropy,larrybradley/astropy,dhomeier/astropy,StuartLittlefair/astropy,tbabej/astropy,kelle/astropy,MSeifert04/astropy,joergdietrich/astropy,aleksandr-bakanov/astropy,DougBurke/astropy,AustereCuriosity/astropy,AustereCuriosity/astropy,bsipocz/astropy,larrybradley/astropy,dhomeier/astropy,mhvk/astropy,StuartLittlefair/astropy,funbaker/astropy,larrybradley/astropy,StuartLittlefair/astropy,aleksandr-bakanov/astropy,astropy/astropy,tbabej/astropy,lpsinger/astropy,saimn/astropy,joergdietrich/astropy,aleksandr-bakanov/astropy,lpsinger/astropy,dhomeier/astropy,MSeifert04/astropy,lpsinger/astropy,DougBurke/astropy,funbaker/astropy,stargaser/astropy,MSeifert04/astropy,mhvk/astropy,lpsinger/astropy,funbaker/astropy,kelle/astropy,saimn/astropy,tbabej/astropy,mhvk/astropy,tbabej/astropy,lpsinger/astropy,astropy/astropy,astropy/astropy,StuartLittlefair/astropy,MSeifert04/astropy,astropy/astropy,pllim/astropy,larrybradley/astropy,joergdietrich/astropy,DougBurke/astropy,pllim/astropy,bsipocz/astropy,saimn/astropy,StuartLittlefair/astropy,bsipocz/astropy,dhomeier/astropy,astropy/astropy,AustereCuriosity/astropy,mhvk/astropy,pllim/astropy,AustereCuriosity/astropy,kelle/astropy,mhvk/astropy,joergdietrich/astropy,larrybradley/astropy,saimn/astropy,kelle/astropy,stargaser/astropy,stargaser/astropy,bsipocz/astropy,aleksandr-bakanov/astropy,pllim/astropy,kelle/astropy,joergdietrich/astropy,funbaker/astropy,AustereCuriosity/astropy,dhomeier/astropy,saimn/astropy,stargaser/astropy,tbabej/astropy