Merge branch 'devel-2.1'

* devel-2.1:
  TestAsyncUDPSocket: remove dead code and add test
  TestAsyncUDPSocket: test for oversized sends
  Document the check-man change
  Update NEWS for Ganeti 2.1.3
  Second attempt at fixing check-man
  Fix check-man for newer man-db
  Add RemoveDir utility function

Conflicts:
	NEWS
	  - trivial
	test/ganeti.daemon_unittest.py
	  - trivial

Signed-off-by: Guido Trotter <ultrotter@google.com>
Reviewed-by: Michael Hanselmann <hansmi@google.com>