ci/macOS: skip python2 on travis macOS

macOS travis builds recently started failing (travis caches were cleared
recently, maybe related). python2 is reasonably covered by linux CI. Not
going to waste time on it for macOS CI.

    ==> Installing python@2
    ==> Downloading https://homebrew.bintray.com/bottles/python@2-2.7.14_3.el_capita
    ==> Pouring python@2-2.7.14_3.el_capitan.bottle.tar.gz
    Error: The `brew link` step did not complete successfully
    The formula built, but is not symlinked into /usr/local
    Could not symlink bin/2to3-2
    Target /usr/local/bin/2to3-2
    is a symlink belonging to python. You can unlink it:
      brew unlink python
    To force the link and overwrite all conflicting files:
      brew link --overwrite python@2
    To list all files that would be deleted:
      brew link --overwrite --dry-run python@2
    Possible conflicting files are:
    /usr/local/bin/2to3-2 -> /usr/local/Cellar/python/2.7.12_1/bin/2to3-2
    /usr/local/bin/2to3-2.7 -> /usr/local/Cellar/python/2.7.12_1/bin/2to3-2.7
    /usr/local/bin/idle -> /usr/local/Cellar/python/2.7.12_1/bin/idle
    ...

.travis.yml

@@ -6,8 +6,6 @@ env:
   global:
     # To force rebuilding of third-party dependencies, set this to 'true'.
     - BUILD_NVIM_DEPS=false
-    # Update PATH for pip.
-    - PATH="$(python2.7 -c 'import site; print(site.getuserbase())')/bin:$PATH"
     # Build directory for Neovim.
     - BUILD_DIR="$TRAVIS_BUILD_DIR/build"
     # Build directory for third-party dependencies.
@@ -69,11 +67,9 @@ jobs:
     - os: osx
       compiler: clang
       osx_image: xcode7.3  # macOS 10.11
-      env: PATH="/usr/local/opt/python@2/bin:$PATH"
     - os: osx
       compiler: gcc
       osx_image: xcode7.3  # macOS 10.11
-      env: PATH="/usr/local/opt/python@2/bin:$PATH"
     - os: linux
       env: CI_TARGET=lint
     - stage: Flaky builds

ci/before_install.sh

@@ -23,20 +23,14 @@ echo 'python info:'
   2>&1 pyenv versions || true
 ) | sed 's/^/  /'
 
-if [[ "${TRAVIS_OS_NAME}" == osx ]]; then
-  echo "Install Python 2."
-  brew install python@2
-fi
-
-echo "Upgrade Python 2 pip."
-pip2.7 -q install --user --upgrade pip
-
 if [[ "${TRAVIS_OS_NAME}" == osx ]]; then
   echo "Upgrade Python 3."
   brew upgrade python
   echo "Upgrade Python 3 pip."
   pip3 -q install --user --upgrade pip
 else
+  echo "Upgrade Python 2 pip."
+  pip2.7 -q install --user --upgrade pip
   echo "Upgrade Python 3 pip."
   # Allow failure. pyenv pip3 on travis is broken:
   # https://github.com/travis-ci/travis-ci/issues/8363

ci/install.sh

@@ -13,16 +13,18 @@ if [[ "${TRAVIS_OS_NAME}" == osx ]]; then
   brew reinstall -s libtool
 fi
 
-# Use default CC to avoid compilation problems when installing Python modules.
-echo "Install neovim module for Python 2."
-CC=cc pip2.7 -q install --user --upgrade neovim
-
 echo "Install neovim module for Python 3."
 # Allow failure. pyenv pip3 on travis is broken:
 # https://github.com/travis-ci/travis-ci/issues/8363
 CC=cc pip3 -q install --user --upgrade neovim || true
 
 if ! [ "${TRAVIS_OS_NAME}" = osx ] ; then
+  # Update PATH for pip.
+  export PATH="$(python2.7 -c 'import site; print(site.getuserbase())')/bin:$PATH"
+  # Use default CC to avoid compilation problems when installing Python modules.
+  echo "Install neovim module for Python 2."
+  CC=cc pip2.7 -q install --user --upgrade neovim
+
   echo "Install neovim RubyGem."
   gem install --no-document --version ">= 0.2.0" neovim
 fi