Router creation template should contain the sentence based on the actual use-case

[Beth Elwell]

Description of problem:
Router creation template should contain the sentence based on the actual use-case.

Actual results:
Currently, the template contains the following sentence.
openstack_dashboard/dashboards/project/routers/templates/routers/ports/_create.html

{% trans "The default IP address of the interface created is a gateway of the selected subnet. You can specify another IP address of the interface here. You must select a subnet to which the specified IP address belongs to from the above list." %}

This sentence should be improved with the actual use-case.

For example, if the router connected to the private network which has a router already, the IP address has to be specified for the new router.

Expected results:
The following sentence will reduce the confusion in user side.

~~~
If you don't specify an IP address here, the gateway's IP address of the subnet will be assigned to the newly created interface of the router.
If you need to use another IP address or the gateway's IP address has already been in use, please specify another IP address here.
You must specify an IP address which belongs to the selected subnet.
~~~

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/489170

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/489170
Committed: https://git.openstack.org/cgit/openstack/horizon/commit/?id=c4ab26bb64c8038d18206456a42b4732d7901001
Submitter: Jenkins
Branch: master

commit c4ab26bb64c8038d18206456a42b4732d7901001
Author: Beth Elwell <email address hidden>
Date: Mon Jul 31 11:23:32 2017 +0100

    Reduce user confusion in router creation template

    Router creation template should contain the sentence based on the actual
    use-case.

    For example, if the router connected to the private network which has a
    router already, the IP address has to be specified for the new router.

    Change-Id: Ie9ddfba539369ab1035755fdf78bf55422952da4
    Closes-Bug: #1707617

[OpenStack Infra (hudson-openstack)]

This issue was fixed in the openstack/horizon 12.0.0.0rc1 release candidate.