systemd: Do not unmount /storage and /flash at shutdown as this always fails

packages/sysutils/systemd/patches/systemd-09_ignore-storage-flash-mount-points.patch

@@ -0,0 +1,15 @@
+diff -Naur a/src/core/mount-setup.c b/src/core/mount-setup.c
+--- a/src/core/mount-setup.c	2016-07-17 21:54:48.947510924 +0100
++++ b/src/core/mount-setup.c	2016-07-17 21:56:02.708552744 +0100
+@@ -121,7 +121,10 @@
+         /* Container bind mounts */
+         "/proc/sys\0"
+         "/dev/console\0"
+-        "/proc/kmsg\0";
++        "/proc/kmsg\0"
++        /* LibreELEC: always busy */
++        "/flash\0"
++        "/storage\0";
+ 
+ bool mount_point_is_api(const char *path) {
+         unsigned i;