Misleading reconnection log message in AbstractEndpoint.notifyChannelInactive

AbstractEndpoint.notifyChannelInactive logs a message saying it's attempting a reconnection, even if it isn't (due to an orderly disconnect).

To reproduce the issue:

CouchbaseCluster cluster = CouchbaseCluster.create(host);

Bucket bucket = cluster.openBucket("travel-sample");

cluster.disconnect();

Observe the log output contains a line like:

2017-08-18 11:07:03 INFO  Endpoint:547 - [null][KeyValueEndpoint]: Got notified from Channel as inactive, attempting reconnect.

even though the reconnection attempt is skipped because the channel is in a disconnected/ing lifecycle state.

The code should probably only emit that message if it's actually going to connect, and log a different message for an orderly disconnect.