platforms/server: Drop the var subvolume for now

At the moment, the resulting image breaks because of an issue
where the subvolumes aren't mounted before the data is synced
to it as part of the image build.

Reference: https://github.com/OSInside/kiwi/issues/2356

platforms/server.xml

@@ -11,7 +11,6 @@
 			<systemdisk name="fedora">
 				<volume name="@root=root"/>
 				<volume name="home" parent="/"/>
-				<volume name="var" parent="/"/>
 			</systemdisk>
 			<oemconfig>
 				<oem-resize>false</oem-resize>