data: Replace override schema with per-desktop override

GSettings now recognizes per-desktop overrides that can be used
to change schemas' default values for classic mode, so use that
instead of the separate override schema we currently use with
mutter's custom override mechanism.

https://bugzilla.gnome.org/show_bug.cgi?id=786496

data/00_org.gnome.shell.extensions.classic.gschema.override

@@ -0,0 +1,5 @@
+[org.gnome.mutter:GNOME-Classic]
+dynamic-workspaces=false
+
+[org.gnome.desktop.wm.preferences:GNOME-Classic]
+button-layout='appmenu:minimize,maximize,close'

data/meson.build

@@ -59,5 +59,5 @@ custom_target(style + '.css',
 
 install_data(theme_data, install_dir: themedir)
 
-classic_schema = 'org.gnome.shell.extensions.classic-overrides.gschema.xml'
-install_data(classic_schema, install_dir: schemadir)
+classic_override = '00_org.gnome.shell.extensions.classic.gschema.override'
+install_data(classic_override, install_dir: schemadir)

data/org.gnome.shell.extensions.classic-overrides.gschema.xml

@@ -1,46 +0,0 @@
-<schemalist>
-  <schema id="org.gnome.shell.extensions.classic-overrides"
-          path="/org/gnome/shell/extensions/classic-overrides/"
-	  gettext-domain="gnome-shell-extensions">
-    <key name="attach-modal-dialogs" type="b">
-      <default>true</default>
-      <summary>Attach modal dialog to the parent window</summary>
-      <description>
-        This key overrides the key in org.gnome.mutter when running
-        GNOME Shell.
-      </description>
-    </key>
-
-    <key name="button-layout" type="s">
-      <default>"appmenu:minimize,maximize,close"</default>
-      <summary>Arrangement of buttons on the titlebar</summary>
-      <description>
-        This key overrides the key in org.gnome.desktop.wm.preferences when running GNOME Shell.
-      </description>
-    </key>
-
-    <key name="edge-tiling" type="b">
-      <default>true</default>
-      <summary>Enable edge tiling when dropping windows on screen edges</summary>
-      <description>
-        This key overrides the key in org.gnome.mutter when running GNOME Shell.
-      </description>
-    </key>
-
-    <key name="workspaces-only-on-primary" type="b">
-      <default>true</default>
-      <summary>Workspaces only on primary monitor</summary>
-      <description>
-        This key overrides the key in org.gnome.mutter when running GNOME Shell.
-      </description>
-    </key>
-
-    <key name="focus-change-on-pointer-rest" type="b">
-      <default>true</default>
-      <summary>Delay focus changes in mouse mode until the pointer stops moving</summary>
-      <description>
-        This key overrides the key in org.gnome.mutter when running GNOME Shell.
-      </description>
-    </key>
-  </schema>
-</schemalist>

po/POTFILES.in

@@ -1,6 +1,5 @@
 data/gnome-classic.desktop.in
 data/gnome-classic.session.desktop.in
-data/org.gnome.shell.extensions.classic-overrides.gschema.xml
 extensions/alternate-tab/prefs.js
 extensions/apps-menu/extension.js
 extensions/auto-move-windows/extension.js