sysupgrade: create state file so procd knows when a sysupgrade is in progress

Signed-off-by: John Crispin <[email protected]>

SVN-Revision: 36893

package/base-files/files/sbin/sysupgrade

@@ -180,6 +180,7 @@ fi
 run_hooks "" $sysupgrade_pre_upgrade
 
 ubus call system upgrade
+touch /tmp/sysupgrade
 
 kill_remaining TERM
 sleep 3