Merge branch 'stable-2.5' into devel-2.5

* stable-2.5:
  Fix type check for OpQuery.filter
  Fix explanation of gnt-node evacuate --primaries-only
  Makefile.am: fix permissions for Python scripts on install
  devel/upload: Fix permissions for installed directories
  Fix cluster verification issues on multi-group clusters

Signed-off-by: Michael Hanselmann <hansmi@google.com>
Reviewed-by: René Nussbaumer <rn@google.com>