ci/travis: Enable ipv6 #12182

ref: a39c8b7ce3
ref: bfe13ccc58

Also:
- Remove unused macos_rvm_dance() function. (It was there for reference,
  but we have since resolved (or gave up) on Travis + macOS + ruby.

ci/before_script.sh

@@ -10,6 +10,12 @@ fi
 CI_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
 source "${CI_DIR}/common/build.sh"
 
+# Enable ipv6 on Travis. ref: a39c8b7ce30d
+if ! test "${TRAVIS_OS_NAME}" = osx ; then
+  echo "before_script.sh: enable ipv6"
+  sudo sysctl -w net.ipv6.conf.lo.disable_ipv6=0
+fi
+
 # Test some of the configuration variables.
 if [[ -n "${GCOV}" ]] && [[ ! $(type -P "${GCOV}") ]]; then
   echo "\$GCOV: '${GCOV}' is not executable."

ci/common/build.sh

@@ -86,12 +86,3 @@ build_nvim() {
 
   cd "${TRAVIS_BUILD_DIR}"
 }
-
-macos_rvm_dance() {
-  # neovim-ruby gem requires a ruby newer than the macOS default.
-  source ~/.rvm/scripts/rvm
-  rvm get stable --auto-dotfiles
-  rvm reload
-  rvm use 2.2.5
-  rvm use
-}