volume action description clean-up

[Gloria Gu]

Need a minor message clean-up for project->volume for retype and upload-to-image actions based on the clean up effort in https://review.openstack.org/#/c/104334/

This is the part of the follow-up per Lin hua Cheng's comment on https://review.openstack.org/#/c/112104/

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/119134

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/119134
Committed: https://git.openstack.org/cgit/openstack/horizon/commit/?id=43b4dd8ddcee2ed6fb18e68ee6d3d011566e3c26
Submitter: Jenkins
Branch: master

commit 43b4dd8ddcee2ed6fb18e68ee6d3d011566e3c26
Author: Gloria Gu <email address hidden>
Date: Thu Sep 4 09:57:06 2014 -0700

    Description clean-up for volume actions

    Some minor description clean-ups for volume action
    'change volume type' and 'upload to image' to remove
    'From here you can'.

    Also remove unecessary 'required=True' for the field.

    Closes-Bug: #1364623

    Change-Id: Ia8c1a593e80abf193f26f7cb97bc1ba383383399