Merge branch 'stable-2.1' into devel-2.1

* stable-2.1:
  Add NLD constants to Ganeti
  Fix two potentially endless loops in http library
  Fix bug in LUQueryConfigValues
  Fix typo in LUVerifyCluster when checking node time

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