Upgrade bazlets to latest stable-2.16 to build with 2.16.15 API
Upgrade bazlets to latest stable-2.16 to build with 2.16.15 API

Change-Id: I6f7d7e7070018d438f723d02ac260d5f6869051a

GerritCodeReview/plugins_delete-project,GerritCodeReview/plugins_delete-project,GerritCodeReview/plugins_delete-project,GerritCodeReview/plugins_delete-project