Fix typo in rabbitmq.config.erb template

[jakshi]

Fix typo in rabbitmq.config.erb template, superflous single quote in ssl_port.
Without this fix rabbit.config looks like:
{ssl_listeners, [5671]'},
that breaks rabbitmq start with message about absence of dot in the end of config file.

[portertech]

Cool, this has already be done in #18, and is still awaiting attention, COOK-1552. cc @jtimberman

(edited, referenced another PR at first)

[stevendanna]

Looks like #18 was resolved, and this can be closed.