[FS#1270] flock dependency needed for sysntpd

[LEDE Bugs]

A new Flyspray task has been opened.  Details are below. 

User who did this - ratsputin (ratsputin) 

Attached to Project - LEDE Project
Summary - flock dependency needed for sysntpd
Task Type - Bug Report
Category - Base system
Status - Unconfirmed
Assigned To - 
Operating System - All
Severity - Low
Priority - Very Low
Reported Version - Trunk
Due in Version - Undecided
Due Date - Undecided
Details - Supply the following if possible:
 - Device problem occurs on: Linksys WRT3200ACM
 - Software versions of LEDE release, packages, etc.: OpenWrt SNAPSHOT r5756-9a9c7fb4cf / LuCI Master (git-18.011.81190-196419f)
 - Steps to reproduce
   
- Build OpenWRT from sources using make menuconfig / make
- Boot router
The following message shows up in logread:

daemon.notice procd: /etc/init.d/sysntpd: /etc/rc.common: /lib/functions/procd.sh: line 512: flock: not found

More information can be found at the following URL:
https://bugs.lede-project.org/index.php?do=details&task_id=1270