[rabbitmq-server/epel7] (4 commits) ...fix failure to start on boot on RHEL7

[Pádraig Brady]

Summary of changes:

14ee539... Use ephemeral port for probing (*)
  7c340ac... Use ephemeral port (32768 and up instead of 10000+) (RHBZ#9 (*)
  a1fbd96... Fix race in systemd service startup (RHBZ#1059913). (*)
  d106ca9... fix failure to start on boot on RHEL7

(*) This commit already existed in another branch; no separate mail sent