Log Message:
Update net/rabbitmq-c to 0.6.0.

Changes since v0.5.2:
- Tools: Enable support for SSL in tools.
- Lib: ABI CHANGE: enable support for auto_delete, internal flags
  to amqp_exchange_declare
- Lib: check for double-close in SSL/TCP socket impl
- Lib: allocate struct when method has no field.
- Lib: add support for SANs in OpenSSL socket impl.
- Lib: add functions to get negotiated frame_max and heartbeat parms.