Partial Fix - Give o-c-c children time to exit

When the playbook runs, we intentionally stop os-collect-config, but
what we've forgotten is that while os-collect-config may no longer be
running, processes spawend by os-collect-config could still be
running until they exit.

As such, inserting a 30 second pause after stopping os-collect-config
to give os-refresh-config time to complete any current run.

Change-Id: I475a00e2e2670add69c8bcc204c5b74840f1cb15