fix histogram bug
fix histogram bug

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