Merge branch 'stable-2.15'

* stable-2.15:
  Update bazlets to latest revision on stable-2.15
  Bazel: Harmonize names of external repositories
  Update javamelody-core to 1.72.0
  Update bazlets to latest revision on stable-2.14

Change-Id: Ibd7cdddc7d30f7d57c9d4de571fe65d9c39fea7a