Change router's property name "agent_id" to "l3_agent_id"

[Mitsuru Kanabuchi]

Currently, the OS::Neutron::Router supports associating the L3Agent via "agent_id" property.

However, Neutron support few kind of agents(L3, DHCP and etc).
The property name of "agent_id" is little bit ambiguous.

It's nice to change property name "agent_id" to "l3_agent_id".

Related review:
  https://review.openstack.org/#/c/81726/

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/82716

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/82716
Committed: https://git.openstack.org/cgit/openstack/heat/commit/?id=0eb5dc5de2d978d08631ffc8bec2327d4cd9d64b
Submitter: Jenkins
Branch: master

commit 0eb5dc5de2d978d08631ffc8bec2327d4cd9d64b
Author: Mitsuru Kanabuchi <email address hidden>
Date: Tue Mar 25 14:08:22 2014 +0900

    Change router's prop name agent_id to l3_agent_id

    Currently, the OS::Neutron::Router supports associating the L3Agent via
    "agent_id" property.

    However, Neutron supports a few kind of agents(L3, DHCP and etc).
    The property name of "agent_id" is little bit ambiguous.

    It's nice to change property name "agent_id" to "l3_agent_id".

    Change-Id: Ie3c90d703df81bbf9d541a7d7c08641eed9c8e2a
    Closes-bug: #1296608