Eureka should log the total number of instances

Eureka client would only log the number of UP instances but with the
deceiving message:

logger.debug("The total number of instances in the client now is {}",
                totInstances);
Fix appsHashCode not getting updated

appsHashCode was not getting updated under 2 circumstances.

First when a BackupRegistry is used at all. Second when
fetchRegistry is called. Most notably when this is called
by the CacheRefreshThread.
Merge pull request #130 from Knewton/fix-instance-count-log

Fix Eureka instance count and status logging