Last contact for tablet server on monitor seemed incorrect

[keith-turner]

Describe the bug

Working with a handful of half dead tablet sever that were holding their locks in zookeeper but not accepting RPC request it seems the last contact times for these tablet servers was always within the last few seconds. However I do not think the manager was successfully contacting them. It is possible I made a mistake, want to try to reproduce this and opening this issue as a reminder.

Versions (OS, Maven, Java, and others, as appropriate):

• Affected version(s) of this project: 2.1.x

Expected behavior

The last contact time increases when tablet server can not be contacted.