Make sure we confirm anything apt asks us

Author: ignisf

.travis.yml

@@ -37,7 +37,7 @@ bundler_args: --jobs=4 --retry=3
 before_install:
   - if [ "$TRAVIS_OS_NAME" == "linux" ]; then gem update bundler; fi
   - if [ "$TRAVIS_OS_NAME" == "linux" ]; then sudo apt-get update; fi
-  - if [ "$TRAVIS_OS_NAME" == "linux" ]; then sudo apt-get upgrade binutils; fi
+  - if [ "$TRAVIS_OS_NAME" == "linux" ]; then sudo apt-get upgrade -y binutils; fi
   - if [ "$TRAVIS_OS_NAME" == "osx" ]; then sudo gem install bundler; fi
 script:
   - git submodule update --init