Wait until shutdown for at least 5mins

Before, the timeout was kind of hardcoded to 5 mins. The intention is
that it should follow the general wait timeout, but not be *under* 5
minutes. This should fix that.
Make busy port timeout configurable

We are getting test failures where we are timing out seconds before the
busy dist port message appears in the log.

Backport busy dist port timeout fix to 1.3