Do not install preinstalled Android components on Travis
Do not install preinstalled Android components on Travis

On Docker-based VMs, Travis has an issue
(https://github.com/travis-ci/travis-ci/issues/2848), it cannot update
already installed Android dependencies, and fails the build while doing
that. To work around this problem, we remove those dependencies from
the Travis script for now. We should readd them in the future, since
the list of preinstalled dependencies may change:
http://docs.travis-ci.com/user/languages/android/#Pre-installed-components

b-cuts/m2e-android,b-cuts/m2e-android,WonderCsabo/m2e-android,rgladwell/m2e-android,WonderCsabo/m2e-android,rgladwell/m2e-android