Apache ActiveMQ 6.2.4

What's Changed

• [6.2.x] Bump version to 6.2.4-SNAPSHOT by @jbonofre in #1868
• [6.2.x] Ensure AMQP protocol marshals messages before passing to broker (#1859) by @cshannon in #1860
• [6.2.x] Backport MQTT fixes by @cshannon in #1884
• [6.2.x] Properly handle SSL handshake updates by @cshannon in #1886

Full Changelog: activemq-6.2.3...activemq-6.2.4