teuth: rgw task example config update

Due to bug #5716, pools need to start with a '.' at present.
Updating the examples to follow this convention.

Signed-off-by: Joe Buck <jbbuck@gmail.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
teuth: fix issue in cleanup code

The post-yield code in create_dirs needed to
be tweaked to correctly delete the {tdir}/apache
directory (if it exists) on each client.

Signed-off-by: Joe Buck <jbbuck@gmail.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>