Removing all messages from undeployed channel does not clear source connector statistics

[rbeckman-nextgen]

This was introduced in rev 7698 for MIRTH-2288.

We gave DonkeyEngineController.RemoveAllMessagesTask a way of removing all messages for an undeployed channel but when clearing statistics we don't include the source connector.

We reset statistics for the channel and all destination connectors but I think as an oversight we just dont include the source connector.
`
if (clearStatistics) {
Set statuses = Statistics.getTrackedStatuses();
dao.resetStatistics(channelId, null, statuses);

 for (com.mirth.connect.model.Connector connector : channelModel.getDestinationConnectors()) {
 dao.resetStatistics(channelId, connector.getMetaDataId(), statuses);
 }

}
`

I believe the simple fix would just be to add:

dao.resetStatistics(channelId, 0, statuses);

Also I noticed that in ChannelController.resetStatistics we actually commit each dao operation separately to avoid deadlocks, I'm not sure if that precaution needs to be taken into for this method as well.

Imported Issue. Original Details:
Jira Issue Key: MIRTH-3927
Reporter: eduardoa
Created: 2016-04-19T14:53:10.000-0700