Add keepalive option to rabbitmq config

Add keepalive and other socket options to the rabbitmq config.
This instructs rabbitmq to apply keepalive to its sockets, based on the
global keepalive settings, which can be configured via the sysctl
element.

Default is for rabbitmq keepalive to be enabled.

Change-Id: I4fa26f9cab0ecfe39698a3ef5ac440e2892450d3
Merge "Add keepalive option to rabbitmq config"