Update .travis.yml to fix latest integration errors.
Update .travis.yml to fix latest integration errors.

Revert to Ubuntu 14.04 LTS

Nefertumm/azerothcore-wotlk,azerothcore/azerothcore-wotlk,Nefertumm/azerothcore-wotlk,polaretto/azerothcore-wotlk,Helias/azerothcore-wotlk,mygithome002/azerothcore-wotlk,azerothcore/azerothcore-wotlk,mygithome002/azerothcore-wotlk,Nefertumm/azerothcore-wotlk,mygithome002/azerothcore-wotlk,jokerlfm/azerothcore-wotlk,ShinDarth/azerothcore-wotlk,mygithome002/azerothcore-wotlk,Helias/azerothcore-wotlk,jokerlfm/azerothcore-wotlk,Helias/azerothcore-wotlk,Helias/azerothcore-wotlk,azerothcore/azerothcore-wotlk,Nefertumm/azerothcore-wotlk,polaretto/azerothcore-wotlk,mygithome002/azerothcore-wotlk,jokerlfm/azerothcore-wotlk,jokerlfm/azerothcore-wotlk,jokerlfm/azerothcore-wotlk,azerothcore/azerothcore-wotlk,Helias/azerothcore-wotlk,Helias/azerothcore-wotlk,ShinDarth/azerothcore-wotlk,polaretto/azerothcore-wotlk,polaretto/azerothcore-wotlk,ShinDarth/azerothcore-wotlk,azerothcore/azerothcore-wotlk,mygithome002/azerothcore-wotlk,jokerlfm/azerothcore-wotlk,Nefertumm/azerothcore-wotlk,Nefertumm/azerothcore-wotlk,azerothcore/azerothcore-wotlk,ShinDarth/azerothcore-wotlk