Reduced travis-ci build to jdk7 again
Reduced travis-ci build to jdk7 again

mp911de/lettuce,lettuce-io/lettuce-core,lettuce-io/lettuce-core,Hocdoc/lettuce,taer/lettuce,Hocdoc/lettuce,lettuce-io/lettuce-core,taer/lettuce,pulse00/lettuce,mp911de/lettuce,lettuce-io/lettuce-core,pulse00/lettuce