Update .travis.yml for Sage 9
Update .travis.yml for Sage 9

gkmurray/sage,ChrisLTD/sage,ChrisLTD/sage,mckelvey/sage,sacredwebsite/sage,levito/kleineweile-wp-theme,democracy-os-fr/sage,teaguecnelson/tn-tellis-bds,c50/c50_roots,kalenjohnson/sage,levito/kleineweile-wp-theme,kalenjohnson/sage,PCHC/pharmacyresidency2017,JulienMelissas/sage,kalenjohnson/sage,JulienMelissas/sage,roots/sage,gkmurray/sage,teaguecnelson/tn-tellis-bds,generoi/sage,c50/c50_roots,ChrisLTD/sage,NicBeltramelli/sage,NicBeltramelli/sage,skemantix/sage,gkmurray/sage,JulienMelissas/sage,teaguecnelson/tn-tellis-bds,ptrckvzn/sage,agusgarcia/sage9,gkmurray/sage,PCHC/pharmacyresidency2017,sacredwebsite/sage,sacredwebsite/sage,PCHC/pharmacyresidency2017,ptrckvzn/sage,generoi/sage,levito/kleineweile-wp-theme,ptrckvzn/sage,generoi/sage,democracy-os-fr/sage,mckelvey/sage,democracy-os-fr/sage,ChrisLTD/sage,mckelvey/sage,agusgarcia/sage9,roots/sage,agusgarcia/sage9,skemantix/sage,skemantix/sage,NicBeltramelli/sage,c50/c50_roots