App Engine: Update to sdk version 1.9.8, as 1.9.6 was taken down
Merge pull request #163 from Joshua-Anderson/google-appengine-patch-1

App Engine: Update to sdk version 1.9.8, as 1.9.6 was taken down
Releases: Switch to using $TRAVIS_TAG. Fixes #162 and travis-ci/travis-ci#2510