Upgrades, handle socket.timeout exception in health checker

It happens not often, but sometimes
when we make http call, it raises
socket.timeout exception.

* handle socket.timeout exception
  in health checker
* also fixed wrong log message
  in health checker

Change-Id: I9f90540a6ea3687b0f9fd640242af02e50c5d484
Closes-bug: #1362508
Merge "Upgrades, handle socket.timeout exception in health checker"