Update git submodules

* Update plugins/gitiles from branch 'master'
  to b90db6dd4c43294e94523222a9ee57a65d11d058
  - Merge branch 'stable-2.16'
    
    * stable-2.16:
      Upgrade bazlets to latest stable-2.15 to build with 2.15.10 API
      Upgrade bazlets to latest stable-2.16 to build with 2.16.4 API
      Upgrade bazlets to latest stable-2.15 to build with 2.15.9 API
      Upgrade bazlets to latest stable-2.15 to build with 2.15.8 API
      Upgrade bazlets to latest stable-2.14 to build with 2.14.18 API
      Bazel: Include eclipse-out directory in .bazelignore
      Add explanatory comment to empty BUILD file(s)
    
    Change-Id: I0467ee0dced8cc5109def53be2db21d03cfcdcdc
    
  - Merge branch 'stable-2.15' into stable-2.16
    
    * stable-2.15:
      Upgrade bazlets to latest stable-2.15 to build with 2.15.10 API
    
    Change-Id: I08fae3342c9f2a228a90f6111f3862f8170a47f0
    
  - Upgrade bazlets to latest stable-2.15 to build with 2.15.10 API
    
    Change-Id: Id11f7812c7e60694cc3844de982203411c93bc07
    
  - Merge branch 'stable-2.15' into stable-2.16
    
    * stable-2.15:
      Upgrade bazlets to latest stable-2.15 to build with 2.15.9 API
      Upgrade bazlets to latest stable-2.15 to build with 2.15.8 API
      Upgrade bazlets to latest stable-2.14 to build with 2.14.18 API
      Bazel: Include eclipse-out directory in .bazelignore
      Add explanatory comment to empty BUILD file(s)
    
    Change-Id: Ibcbf7f766db422b78aa908b5eb0d7c0abbe29870
    
  - Upgrade bazlets to latest stable-2.16 to build with 2.16.4 API
    
    Change-Id: If7661de29f4275e17485347b839e5f9cf435b666
    
  - Upgrade bazlets to latest stable-2.15 to build with 2.15.9 API
    
    Change-Id: I0420add4c27af424214e2916ed4347c8ee6367a2
    
  - Merge branch 'stable-2.14' into stable-2.15
    
    * stable-2.14:
      Upgrade bazlets to latest stable-2.14 to build with 2.14.18 API
    
    Change-Id: I7253e237c4a141350fcf426e7efee58a3e4ec2e0
    
  - Upgrade bazlets to latest stable-2.15 to build with 2.15.8 API
    
    Change-Id: I37a69b9513859283bf51b138d2a18f37d5bf32e0
    
  - Upgrade bazlets to latest stable-2.14 to build with 2.14.18 API
    
    Change-Id: I47b6c7a49d1b09b505f16e9d282af2e499a93bb1
    
  - Merge branch 'stable-2.14' into stable-2.15
    
    * stable-2.14:
      Bazel: Include eclipse-out directory in .bazelignore
    
    Change-Id: If07072fce48702924a3b64df38524dcdc99b1b50
    
  - Bazel: Include eclipse-out directory in .bazelignore
    
    Since [1] (included since 0.17) Bazel added support for a .bazelignore
    file, allowing to specify directories that should be ignored.
    
    [1] bazelbuild/bazel#4888
    
    Change-Id: I8dfd9b5701dfcc85fd51f626af448d0306b02857
    
  - Merge branch 'stable-2.14' into stable-2.15
    
    * stable-2.14:
      Add explanatory comment to empty BUILD file(s)
    
    Change-Id: I1f8704b964327597d0a26ef849b6ab40a077c0c1
    
  - Add explanatory comment to empty BUILD file(s)
    
    Change-Id: Ifc4e5146672ffa35ba45882cafaae82bf9ea5751