The recent Mag TOS work in CarpetX revealed that File.c had a threading problem. It also revealed that the scheduler can sometimes retrace a RDWR declaration. Both of these startup issues need addressing.

PR: https://bitbucket.org/cactuscode/cactus/pull-requests/160

Please Review.

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Ticket URL: https://bitbucket.org/einsteintoolkit/tickets/issues/2784/fix-cactus-startup-problems