Add redis-server to Travis services.
Add redis-server to Travis services.

jaisonerick/lita,mcgain/lita,liamdawson/lita,jimmycuadra/lita,elia/lita,jimmycuadra/lita,byroot/lita,sadiqmmm/lita,natesholland/lita,prsimp/lita,mcgain/lita,PatrickTulskie/lita,litaio/lita,natesholland/lita,elia/lita,jaisonerick/lita,MatthewKrey/lita,sadiqmmm/lita,brodock/lita,litaio/lita,crimsonknave/lita,brodock/lita,MatthewKrey/lita,chriswoodrich/lita,tristaneuan/lita,chriswoodrich/lita,tristaneuan/lita,byroot/lita,liamdawson/lita,crimsonknave/lita