Fix command line in doc for load balancer

[Ton Ngo]

The document shows some command lines for associating a floating ID to the load balancer VIP.
Recently the pool type for etcd was changed so the search patter in the unix grep command now returns 2 entries instead of just the entry for the kubenetes load balancer pool as intended originally.
Users following the example in the doc will get an error.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/234455

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/234455
Committed: https://git.openstack.org/cgit/openstack/magnum/commit/?id=e37276fc1584d60d530c1a69a6ea1918de5dc5bb
Submitter: Jenkins
Branch: master

commit e37276fc1584d60d530c1a69a6ea1918de5dc5bb
Author: Ton Ngo <email address hidden>
Date: Tue Oct 13 21:59:24 2015 +0000

    Fix command line in document example

    Example in document for Kubernetes Load Balancer.

    In the example, the commands to manually associate a floating IP
    to the LB VIP uses grep on "TCP" to find the VIP from the neutron
    list. Recently the etcd pool protocol changes to TCP, so the
    grep now returns 2 entries instead of just the entry for the LB.
    This in turn gives an error in the next command.

    Add another grep to filter out the etcd VIP.

    Change-Id: I619fa09fb4a5db7bacbc5d73e38016b8cd6404c6
    Closes-Bug: 1505780