node, syscontainer: umount everything under /var/lib/docker/containers

Do not leave any mount point busy under /var/lib/docker/containers

Signed-off-by: Giuseppe Scrivano <[email protected]>

Author: giuseppe

images/node/system-container/system-container-wrapper.sh

@@ -1,4 +1,12 @@
 #!/bin/sh
 source /run/$NAME-env
 
+UMOUNT_TARGET=/var/lib/docker/containers
+
+findmnt -R -A -nuo TARGET --raw $UMOUNT_TARGET | tr -d '\r' | grep -v "^$UMOUNT_TARGET$" | \
+while read i;
+do
+    umount -lR $i
+done
+
 exec /usr/local/bin/origin-node-run.sh