Fix problems with cert specifications causing replication_ssl to fail

Fix problem with `cacertdir` specification in `replication_ssl` test. The [code](https://github.com/basho/riak_repl/blob/develop/src/riak_repl_util.erl#L481) used load cert files in v2 replication expects the path specific by the `cacertdir` key to only be a directory. With v3 replication the [code](https://github.com/basho/riak_core/blob/develop/src/riak_core_ssl_util.erl#L135) used is flexible enough to allow a directory or a file. Also, correct a typo in the `certfile` path for the `SSLConfig1` configuration.

These changes get the `replication_ssl` test passing for me locally, but the test does rely on the exhaustion of `rt_max_wait_time` for several conditions so I recommend setting it to a value of `60000` or less for more expedient verification.