Try to install PhantomJS from GitHub.

Bitbucket is very unreliable. Most of our builds are failed because
PhantomJS can’t be downloaded.

PhantomJS maintainers are looking for alternative solutions,
Medium/phantomjs repo is a temporary workaround:
ariya/phantomjs#13953

.travis.yml

@@ -24,8 +24,8 @@ before_script:
 before_install:
   # Update npm to version 3
   - npm install -g npm@'>=3'
-  # Install PhantomJS
+  # Install PhantomJS from https://github.com/Medium/phantomjs
   - mkdir travis-phantomjs
-  - wget https://bitbucket.org/ariya/phantomjs/downloads/phantomjs-2.1.1-linux-x86_64.tar.bz2 -O $PWD/travis-phantomjs/phantomjs-2.1.1-linux-x86_64.tar.bz2
+  - wget https://github.com/Medium/phantomjs/releases/download/v2.1.1/phantomjs-2.1.1-linux-x86_64.tar.bz2
   - tar -xvf $PWD/travis-phantomjs/phantomjs-2.1.1-linux-x86_64.tar.bz2 -C $PWD/travis-phantomjs
   - export PATH=$PWD/travis-phantomjs/phantomjs-2.1.1-linux-x86_64/bin:$PATH