overrides: Get facesdirs setting from gsettings-desktop-schemas
overrides: Get facesdirs setting from gsettings-desktop-schemas

We are moving this setting to gsettings-desktop-schemas so that
gnome-initial-setup can use it without a hard dependency on
gnome-control-center.

Squash with 73e0f7d8abe6c7011d685e1200a52edeaeaee03e on the next rebase.

https://phabricator.endlessm.com/T28364

endlessm/eos-theme