Merge branch 'stable-2.8'

* stable-2.8:
  Update 2.8.2 release notes with recently merged changes.
  Change dialog title from Error to Warning on intraline diff timeout
  Another attempt to fix submit rule evaluation for non blocking labels
  Fix: Label update operation is executed as insert
  RFC: Work around null commit when updating submodules

Change-Id: Icc1ce1698add8321a86af42ed864b02d9ef58040