Update to the latest travis_setup.sh for Scala Native

[densh]

Recent PR changed the location of the travis setup script within a Scala Native repo. This PR updates travis build to point to the new location.

[codecov]

Codecov Report

Merging #458 into master will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master     #458   +/-   ##
=======================================
  Coverage   98.03%   98.03%           
=======================================
  Files          57       57           
  Lines         662      662           
  Branches       12       12           
=======================================
  Hits          649      649           
  Misses         13       13

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[fthomas]

Thanks @densh! Will the script in the master branch work for all versions of Scala Native or should we change to a tagged version of that script on the next Scala Native release (e.g. https://raw.githubusercontent.com/scala-native/scala-native/v0.3.7/scripts/travis_setup.sh)?

[densh]

@fthomas We plan to slowly shrink number of external dependencies in the future, but it's not happening any time soon, so using master is quite safe. We also update it whenever travis environment changes. In any case if you have any issues with travis setup script just let us know on gitter.

[fthomas]

Ok, thanks for the update!