fix for mistakenly not checking for has_row_index before adding idx
fix for mistakenly not checking for has_row_index before adding idx

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