An interrupted connection causes a replicator to stop

Casual analysis suggests that, like Java, Android is reporting an interrupted connection as an unknown error. Unknown errors are non-recoverable and force the replicator to stop.

This is a regression.

Correct resolution is to use Jim Borden's new Standard POSIX codes when reporting the failure to core.

For the 2.8.x products, if it is possible to identify the error, we might be able to report it as a UserDefinedTransient error.

First step is to make sure we understand what's happening. The forum post that generated this ticket is here:

https://forums.couchbase.com/t/replicator-pull-continous-stop-after-network-error-in-couchbase-lite-2-8-x-android/30061/3