Remove pause-file and reset-file support

We don't use the pause-file or reset-file any more, instead we'd
'arcyd stop' and 'arcyd start'.  Remove the dead code to simplify
things.

Test Plan:
$ ./precommit.sh
$ ./testbed/arcyd/loop_test.sh
$ ./testbed/arcyd/test_shell.sh
$ ./testbed/arcyd/acceptance_tests.sh