Use timeout for rndc status in shutdown test

Use timeout for rndc status in shutdown test

Pass 5 second timeout to the rndc status command(s) to avoid hitting the
hard 10 second timeout from subprocess.call, which would result in an
unwanted exception that would only mask the real issue: if the rndc
status times out in this test, it is likely due to the server not
stopping as it should.

(cherry picked from commit ceed694659baaffc6e678e680a0dae33d1a07eca)