Remove memcached configuration from swift task

[OpenStack Infra]

https://review.openstack.org/165025
commit e3867b699c6a32a837e64c4a892e4b56bda38609
Author: Aleksandr Didenko <email address hidden>
Date: Tue Mar 17 12:52:59 2015 +0200

    Remove memcached configuration from swift task

    We configure memcached in a separate task so there's no need to do
    the same in openstack::swift::proxy class, unless we moved swift to
    the separate role.

    Fix pre- post- tests for swift and memcached:
     * Add memcached process check for swift post test
     * Add testcase for memcached should not listen for public ip

    Fix swift::proxy::cache parameter.

    DocImpact: (Ops guide) if the memcached service was restarted, the
      keystone service must be restarted next as well.

    Related-bug: #1432242
    Change-Id: I5e965f12e5ba0003004ae10442d63c358a104367
    Signed-off-by: Bogdan Dobrelya <email address hidden>