Merge branch 'devel-2.1' into devel-2.2

* devel-2.1:
  Increase version to 2.1.7
  Update NEWS for the 2.1.7 release

Conflicts:
	NEWS
	  - merge
	configure.ac
	  - keep the 2.2 version

Signed-off-by: Guido Trotter <ultrotter@google.com>
Reviewed-by: Iustin Pop <iustin@google.com>