Windows: Fixes comment

Signed-off-by: John Howard <jhoward@microsoft.com>

daemon/archive_windows.go

@@ -4,7 +4,8 @@ package daemon
 // cannot be in a read-only volume. If it  is not in a volume, the container
 // cannot be configured with a read-only rootfs.
 //
-// This is a no-op on Windows which does not support volumes.
+// This is a no-op on Windows which does not support read-only volumes, or
+// extracting to a mount point inside a volume. TODO Windows: FIXME Post-TP4
 func checkIfPathIsInAVolume(container *Container, absPath string) (bool, error) {
 	return false, nil
 }