Revert https://codereview.chromium.org/1291903002 (protobuf roll).

third_party/protobuf/ruby/travis-test.sh

-#!/usr/bin/env bash
-
-# Exit on any error.
-set -e
-
-test_version() {
-  version=$1
-  if [ "$version" == "jruby" ] ; then
-    # No conformance tests yet -- JRuby is too broken to run them.
-    bash --login -c \
-      "rvm install $version && rvm use $version && \
-       which ruby && \
-       gem install bundler && bundle && \
-       rake test"
-  else
-    bash --login -c \
-      "rvm install $version && rvm use $version && \
-       which ruby && \
-       gem install bundler && bundle && \
-       rake test && \
-       cd ../conformance && \
-       make test_ruby"
-  fi
-}
-
-test_version $1