Update RecoverableNetworkWordCount.scala

Trying this example, I missed the moment when the checkpoint was iniciated

Author: comcmipi <pitonak@fns.uniba.sk>

Closes #2735 from comcmipi/patch-1 and squashes the following commits:

b6d8001 [comcmipi] Update RecoverableNetworkWordCount.scala
96fe274 [comcmipi] Update RecoverableNetworkWordCount.scala