datapath: Don't dump partial action lists in flows.

datapath: Don't dump partial action lists in flows.

After commit 9b405f1aa8d175dc63ad3ffe5d0fe05d5ee09162 (datapath: More
flexible kernel/userspace tunneling attribute.), it was possible for a
flow dump to return a partial action list.  It's better to return no
action list at all in this situation since then userspace will know
that it should request the full thing if it wants rather than have
incorrect results.  Therefore, this prevents those partial lists in
situations where we have a very large number of actions.

Signed-off-by: Ben Pfaff <blp@nicira.com>
Signed-off-by: Jesse Gross <jesse@nicira.com>