Add minimal build option
    
    RabbitMQ requires all of erlang, and thus, pulls
    in wxGTK. On an OpenStack system, this means that
    ALL OF X, libmesa-GL, and so forth get pulled in
    as a dependency of rabbitmq-server, which is
    absurd.
    
    The erlang packaging is being updated in F21 to
    make wxGTK and other bits optional. When that
    work is completed, the plan is to replace this
    package with the updated one and perhaps
    move it to the LPC.
    
    This "minimal" erlang package has been able to
    start up RabbitMQ with SSL enabled.
    
    Signed-off-by: Lon Hohberger <lhh@redhat.com>