Handle RabbitMQ errors more gracefully

@Wikia/platform-team 
https://wikia-inc.atlassian.net/browse/PLATFORM-340
Don't know why I was re-throwing the caught exception, so I cleaned that up. The error in the JIRA was from an exception when trying to connect, though, so I also added a try/catch around that.
\RuntimeException, but nothing AMQP specific. Though I suppose that there's probably zero chance that another \RuntimeException will come up through these calls.