Merge pull request #10574 from SvenDowideit/docker-stats-limited-to-libcontainer

For now, docker stats appears to be libcontainer only
Upstream-commit: 68b0ed54cb7ed9e4b66e8a9e0708577b32088de2
Component: engine

components/engine/docs/sources/reference/commandline/cli.md

@@ -2028,6 +2028,8 @@ more details on finding shared images from the command line.
 
       --help=false       Print usage
 
+> **Note**: this functionality currently only works when using the *libcontainer* exec-driver.
+
 Running `docker stats` on multiple containers
 
     $ sudo docker stats redis1 redis2