Fix OperationSwitch so that it does not onComplete() before inner and
outer subscription completes.
Fix OperationSwitch so that it does not onComplete() before inner and
outer subscription completes.
Do not unsubscribe from child once parent has been completed.

Child should not be unsubscribed when the parent complete because it may not be completed.
Merge pull request #443 from ylecaillez/master

OperationSwitch notify onComplete() too early.