tests: test/mon/mon-handle-forward.sh uses ceph-helpers.sh

tests: test/mon/mon-handle-forward.sh uses ceph-helpers.sh

Use ceph-helpers.sh instead of  mon/mon-test-helpers.sh.

  * modifying the .asok and .log names to match the ceph-helpers.sh
    conventions

  * use explicit ports 7300 and 7301 instead of +1 so that grep
    will show that 7301 is used. This reduces the odds of a
    port collision when looking for a port that's not already
    used by an existing test.

Signed-off-by: Loic Dachary <ldachary@redhat.com>