Specify sphinx version explicitly in .travis.yml
Specify sphinx version explicitly in .travis.yml

Sphinx 1.2.3 causes failures in master due to an issue that will be resolved in astropy-helpers 0.4.2. This is a temporary solution until astropy-helpers 0.4.2 is released.
larrybradley/astropy,AustereCuriosity/astropy,bsipocz/astropy,AustereCuriosity/astropy,funbaker/astropy,larrybradley/astropy,StuartLittlefair/astropy,kelle/astropy,AustereCuriosity/astropy,mhvk/astropy,bsipocz/astropy,larrybradley/astropy,aleksandr-bakanov/astropy,MSeifert04/astropy,MSeifert04/astropy,AustereCuriosity/astropy,pllim/astropy,saimn/astropy,joergdietrich/astropy,saimn/astropy,tbabej/astropy,stargaser/astropy,bsipocz/astropy,kelle/astropy,funbaker/astropy,lpsinger/astropy,tbabej/astropy,lpsinger/astropy,MSeifert04/astropy,lpsinger/astropy,DougBurke/astropy,pllim/astropy,dhomeier/astropy,lpsinger/astropy,aleksandr-bakanov/astropy,saimn/astropy,MSeifert04/astropy,saimn/astropy,kelle/astropy,astropy/astropy,StuartLittlefair/astropy,funbaker/astropy,DougBurke/astropy,StuartLittlefair/astropy,aleksandr-bakanov/astropy,mhvk/astropy,joergdietrich/astropy,joergdietrich/astropy,pllim/astropy,stargaser/astropy,kelle/astropy,aleksandr-bakanov/astropy,DougBurke/astropy,stargaser/astropy,astropy/astropy,larrybradley/astropy,tbabej/astropy,tbabej/astropy,astropy/astropy,astropy/astropy,AustereCuriosity/astropy,DougBurke/astropy,mhvk/astropy,pllim/astropy,bsipocz/astropy,mhvk/astropy,kelle/astropy,saimn/astropy,dhomeier/astropy,stargaser/astropy,mhvk/astropy,larrybradley/astropy,astropy/astropy,lpsinger/astropy,dhomeier/astropy,dhomeier/astropy,funbaker/astropy,StuartLittlefair/astropy,pllim/astropy,joergdietrich/astropy,tbabej/astropy,dhomeier/astropy,joergdietrich/astropy,StuartLittlefair/astropy