Don't wait for allowed_failures on travis builds?

[dstufft]

Currently we have a matrix item in Travis for allowed_failure. This is fine to do, but travis won't mark the build successful or failed until that job has finished even though it won't ultimately effect the outcome. One option we can do is to set:

matrix:
  fast_finish: true

Which will tell travis to report the status of the job as soon as all of the non allowed failure builds are done, while still running the allowed failure build.

[brettcannon]

Fine by me, although knowing the coverage can be useful (but I suspect people will wait to see that report anyway). So I say submit a PR! 😄

[brettcannon]

Documentation of the configuration value: https://docs.travis-ci.com/user/customizing-the-build#Fast-Finishing

[brettcannon]

Thanks for merging and closing, @dstufft !