Fix io.ascii segfault reported in #9922
Fix io.ascii segfault reported in #9922

pllim/astropy,saimn/astropy,dhomeier/astropy,mhvk/astropy,dhomeier/astropy,mhvk/astropy,mhvk/astropy,saimn/astropy,dhomeier/astropy,lpsinger/astropy,saimn/astropy,larrybradley/astropy,larrybradley/astropy,lpsinger/astropy,larrybradley/astropy,StuartLittlefair/astropy,mhvk/astropy,aleksandr-bakanov/astropy,astropy/astropy,astropy/astropy,astropy/astropy,saimn/astropy,aleksandr-bakanov/astropy,StuartLittlefair/astropy,StuartLittlefair/astropy,larrybradley/astropy,lpsinger/astropy,pllim/astropy,pllim/astropy,astropy/astropy,pllim/astropy,mhvk/astropy,pllim/astropy,aleksandr-bakanov/astropy,dhomeier/astropy,StuartLittlefair/astropy,StuartLittlefair/astropy,aleksandr-bakanov/astropy,saimn/astropy,lpsinger/astropy,larrybradley/astropy,dhomeier/astropy,astropy/astropy,lpsinger/astropy