message: CI: use gitlab's own submodule system
  This is experimental.  If it works well, we will do the same in fs.
diff: @@ -5,14 +5,14 @@ variables:
  DRAKE_DEBUG_BACKTRACE: "1"
  DRAKE_EXPLAIN: "1"
  DRAKE_MTIME: "0" # rsync and mtime comparisons don't play along very well
  + GET_SOURCES_ATTEMPTS: "3" # gitlab
  + GIT_SUBMODULE_STRATEGY: "recursive" # gitlab
  PYTHONUNBUFFERED: "1"
  TARFLAGS: "" # Additional flags, e.g., -v.
  x86_64-centos6-gcc4:
  stage: build
  script:
  - - git submodule sync
  - - git submodule update --init --recursive --force
  - git fetch origin --tags
  - pip3 install -r drake/requirements.txt
  - SOURCE_DIR="${CI_PROJECT_DIR}"
  @@ -41,8 +41,6 @@ x86_64-centos6-gcc4:
  x86_64-ubuntu-gcc4:
  stage: build
  script:
  - - git submodule sync --recursive
  - - git submodule update --init --recursive --force
  - git fetch origin --tags
  - pip3 install -r drake/requirements.txt
  - SOURCE_DIR="${CI_PROJECT_DIR}"
  @@ -76,8 +74,6 @@ x86_64-ubuntu-gcc4:
  x86_64-jessie-gcc4:
  stage: build
  script:
  - - git submodule sync --recursive
  - - git submodule update --init --recursive --force
  - git fetch origin --tags
  - pip3 install -r drake/requirements.txt
  - SOURCE_DIR="${CI_PROJECT_DIR}"
  @@ -106,8 +102,6 @@ x86_64-jessie-gcc4:
  x86_64-alpine-gcc:
  stage: build
  script:
  - - git submodule sync --recursive
  - - git submodule update --init --recursive --force
  - git fetch origin --tags
  - pip3 install -r drake/requirements.txt
  - SOURCE_DIR="${CI_PROJECT_DIR}"
  @@ -137,8 +131,6 @@ x86_64-alpine-gcc:
  i386-jessie-gcc4:
  stage: build
  script:
  - - git submodule sync --recursive
  - - git submodule update --init --recursive --force
  - git fetch origin --tags
  - pip3 install -r drake/requirements.txt
  - SOURCE_DIR="${CI_PROJECT_DIR}"
  @@ -167,8 +159,6 @@ i386-jessie-gcc4:
  x86_64-windows-mingw4:
  stage: build
  script:
  - - git submodule sync --recursive
  - - git submodule update --init --recursive --force
  - git fetch origin --tags
  - pip3 install -r drake/requirements.txt
  - SOURCE_DIR="${CI_PROJECT_DIR}"
  @@ -197,8 +187,6 @@ x86_64-windows-mingw4:
  #i686-windows-mingw4:
  # stage: build
  # script:
  -# - git submodule sync --recursive
  -# - git submodule update --init --recursive --force
  # - git fetch origin --tags
  # - mkdir -p ../elle-build ../elle-install
  # - farm/configure --arch i686 --os windows --compiler mingw4 --project Elle --source-dir . --build-dir ../elle-build --install-dir ../elle-install
  @@ -213,8 +201,6 @@ x86_64-windows-mingw4:
  x86_64-osx-clang:
  stage: build
  script:
  - - git submodule sync --recursive
  - - git submodule update --init --recursive --force
  - git fetch origin --tags
  - SOURCE_DIR=$PWD
  - BUILD_DIR=$SOURCE_DIR/../elle-build
  