Added tools/boost_install and libs/headers manual checkout to CI jobs.

.travis.yml

@@ -254,9 +254,10 @@ install:
   - cd ..
   - git clone -b $BOOST_BRANCH --depth 1 https://github.com/boostorg/boost.git boost-root
   - cd boost-root
+  - git submodule update --init libs/headers
   - git submodule update --init tools/build
-  - git submodule update --init libs/config
   - git submodule update --init tools/boostdep
+  - git submodule update --init tools/boost_install
   - cp -r $TRAVIS_BUILD_DIR/* libs/detail
   - python tools/boostdep/depinst/depinst.py detail
   - ./bootstrap.sh