busybox template: mount fstab when available

When running unprivileged, lxc-create will touch a fstab file, with bind-mounts
for the ttys and other devices. Add this entry in the container config.

Signed-off-by: Bogdan Purcareata <bogdan.purcareata@freescale.com>
Acked-by: Serge E. Hallyn <serge.hallyn@ubuntu.com>

templates/lxc-busybox.in

@@ -301,6 +301,10 @@ EOF
     done
     echo "lxc.mount.entry = /sys/kernel/security sys/kernel/security none ro,bind,optional 0 0" >>$path/config
     echo "lxc.mount.auto = proc:mixed sys" >>$path/config
+
+    if [ -f "$path/fstab" ]; then
+        echo "lxc.mount = $path/fstab" >>$path/config
+    fi
 }
 
 remap_userns()