Upgrade travis couchbase version to 4.1.0
Upgrade travis couchbase version to 4.1.0

coltfred/davenport,coltfred/davenport,coltfred/davenport,BobWall23/davenport,BobWall23/davenport,BobWall23/davenport,IronCoreLabs/davenport,IronCoreLabs/davenport,IronCoreLabs/davenport