Fix 6446 regression test when YAML missing and make 6448 replacement
Fix 6446 regression test when YAML missing and make 6448 replacement

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