Remove mention of haproxy-endpoints role

Role was never migrated to usage of haproxy-endpoints role
and included task was used instead the whole time.
With that to reduce complexity and to have unified approach, all mention
of the role and handler are removed from the code.

Change-Id: I4614e0249d65fda1762c6d31d93b3b77babb290e

handlers/main.yml

@@ -43,7 +43,3 @@
   listen:
     - "Restart placement services"
     - "venv changed"
-
-- meta: noop
-  listen: Manage LB
-  when: false