Travis: Assume-yes for PPA addition

Author: jonnor

.travis.yml

@@ -6,9 +6,9 @@ node_js:
 - '0.10'
 before_install:
 - sudo add-apt-repository ppa:ubuntu-toolchain-r/test -y
+- sudo add-apt-repository ppa:boost-latest/ppa -y
 - sudo apt-get update -qq
 - sudo apt-get install g++-5
-- sudo add-apt-repository ppa:boost-latest/ppa
 - sudo apt-get install libboost1.55-dev
 install:
 - npm install