When providing the ability to force coverage printouts to occur, some
code was moved around that allowed the "hash" variable to be used
unitialized. This fixes that.
Thanks to Ben for pointing out the problem.
Bug #1577
Previously, there was no way to induce coverage information to be
displayed; it would only print when the system noticed unusual delays
between polling intervals. Now, production of coverage logs can be
forced with "coverage/log" command in ovs-appctl. Coverage counters may
be reset with "coverage/clear".