HPCC-8800 - Potential lookupjoin deadlock

Possible deadlock since refacotring done in HPCC-3326.
The receiver was stopping too early when all slaves are done, which
could mean not all other packets were received and re-broadcast.

Signed-off-by: Jake Smith <jake.smith@lexisnexis.com>
Remove unnecessary extra stop broadcast

Signed-off-by: Jake Smith <jake.smith@lexisnexis.com>
Remove unecessary and dangerous call to stop() in destructor

Signed-off-by: Jake Smith <jake.smith@lexisnexis.com>
switch order of receiver/sender stop in cancel

Slightly cleaner to stop receiver 1st, as it can add packets to
sender. Although they would be cleared up anyway on sender
destructrion.

Signed-off-by: Jake Smith <jake.smith@lexisnexis.com>
Merge pull request #3961 from jakesmith/hpcc-8800

HPCC-8800 - Potential lookupjoin deadlock

Reviewed-By: Gavin Halliday <gavin.halliday@lexisnexis.com>
Reviewed-By: Richard Chapman <rchapman@hpccsystems.com>