multiple single level wildcard not handled correctly

[Emiliano Bonassi]

E.g. a MQTT subscription to rooms/+/devices/+/status doesn't work because the code translates it in a redis subscription to rooms/*/devices/+/status instead of rooms/*/devices/*/status. This means that no packets will be emitted to the clients which subscribe to this kind of topic patterns.

Mosca is not affected (I'm upgrading from it).

MQTT 3.1.1 allows [it] (http://docs.oasis-open.org/mqtt/mqtt/v3.1.1/os/mqtt-v3.1.1-os.html).