Fixes short-form failed ping message bubbling up

* Modified the get_remote_instance_client to catch the correct
  new exception being raised by the ping client. It was previously
  ServerUnreachable, but recently changed to TimeoutException

Change-Id: I224393d0403df3fc39a84e90a08258d621ba5ee4
Merge "Fixes short-form failed ping message bubbling up"