- Added remainingReapTime field in the table event.
  Wihtout it a node that did not have a state for the element
  was marking the element for deletion setting the max reapTime.
  This was creating the possibility to keep the entry being resync
  between nodes forever avoding the purpose of the reap time
  itself.

- On broadcast of the table event the node owner was rewritten
  with the local node name, this was not correct because the owner
  should continue to remain the original one of the message

Signed-off-by: Flavio Crisciani <flavio.crisciani@docker.com>

- Changed the loop per network. Previous implementation was taking a
  ReadLock to update the reapTime but now with the residualReapTime
  also the bulkSync is using the same ReadLock creating possible
  issues in concurrent read and update of the value.
  The new logic fetches the list of networks and proceed to the
  cleanup network by network locking the database and releasing it
  after each network. This should ensure a fair locking avoiding
  to keep the database blocked for too much time.

  Note: The ticker does not guarantee that the reap logic runs
  precisely every reapTimePeriod, actually documentation says that
  if the routine is too long will skip ticks. In case of slowdown
  of the process itself it is possible that the lifetime of the
  deleted entries increases, it still should not be a huge problem
  because now the residual reaptime is propagated among all the nodes
  a slower node will let the deleted entry being repropagate multiple
  times but the state will still remain consistent.

Signed-off-by: Flavio Crisciani <flavio.crisciani@docker.com>

Make sure that the network is garbage collected after
the entries. Entries to be deleted requires that the network
is present.

Signed-off-by: Flavio Crisciani <flavio.crisciani@docker.com>