[Launch Instance Fix] Enabling loading script from file

[Shaoquan Chen]

In configuration step of Launch Instance work flow, we should allow for uploading script from local file. HTML5 provide a File API which makes it possible

 - Browser support: IE10+, Chrome, FireFox and Safari on Mac.
 - The max length of script allowed it 16K.
 - Validation is still missing.

https://review.openstack.org/#/c/165300/

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/165300

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/165300
Committed: https://git.openstack.org/cgit/openstack/horizon/commit/?id=5bec804f2a40299a9de4694b4b79e65f678a3aa7
Submitter: Jenkins
Branch: master

commit 5bec804f2a40299a9de4694b4b79e65f678a3aa7
Author: Brian Tully <email address hidden>
Date: Wed Apr 1 20:41:29 2015 -0400

    [Launch Instance Fix] Enabling loading script from local file

    In configuration step of Launch Instance work flow, we should allow for
    uploading script from local file. HTML5 provides a File API which makes
    it possible.

     - Browser support: IE10+, Chrome, FireFox and Safari (on Mac).
     - Max length of script is 16K.
     - Validation is added.

    Co-Authored-By: Brian Tully <email address hidden>
    Closes-Bug: 1433438
    Change-Id: I967b4f3e3dbecfc9a95988fdbaa603a731db0a7f