Style: Material Design: Compression warning for view-grid override

[Diana Whitten]

On compressing 'matieral':

Compressing... SassDeprecationWarning: Can't find any matching rules to extend u'.mdi-view-grid' -- thiswill be fatal in 2.0, unless !optional is specified! (at custom/horizon/_icons.scss:10)
WARNING:py.warnings:SassDeprecationWarning: Can't find any matching rules to extend u'.mdi-view-grid' -- thiswill be fatal in 2.0, unless !optional is specified! (at custom/horizon/_icons.scss:10)

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/279336

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/279336
Committed: https://git.openstack.org/cgit/openstack/horizon/commit/?id=4f07279cccc0b68062ebff0701c682f739442488
Submitter: Jenkins
Branch: master

commit 4f07279cccc0b68062ebff0701c682f739442488
Author: Diana Whitten <email address hidden>
Date: Thu Feb 11 17:17:33 2016 -0700

    Material: Compression warning for missing icon

    On compressing the 'material' theme:

    Compressing... SassDeprecationWarning: Can't find any matching rules
    to extend u'.mdi-view-grid' -- thiswill be fatal in 2.0, unless
    !optional is specified! (at custom/horizon/_icons.scss:10)
    WARNING:py.warnings:SassDeprecationWarning: Can't find any matching
    rules to extend u'.mdi-view-grid' -- thiswill be fatal in 2.0, unless
    !optional is specified! (at custom/horizon/_icons.scss:10)

    The icon that we were attempting to replace is this one:
    http://fortawesome.github.io/Font-Awesome/icon/th-large/

    The correct replacement for this, IS in fact view-grid,
    but view-grid is not available in our current version of
    material design icons. We will fall back to view-module
    until we can get this updated:

    https://materialdesignicons.com/icon/view-module

    Closes-bug: #1539971

    Change-Id: If57d8cbd332a219dd5b6d986ce4fc938034533d6