ctdb-tests: Use setup_ctdb_base() for eventscript unit tests

ctdb-tests: Use setup_ctdb_base() for eventscript unit tests

There is currently a directory of symlinks that are copied during test
setup.  These symlinks are updated during installation so they point
to the right place when copied.

Instead, use setup_ctdb_base() during test setup.

Signed-off-by: Martin Schwenke <martin@meltin.net>
Reviewed-by: Amitay Isaacs <amitay@gmail.com>