Revert "Add posix lock on all iptables, ebtables and ipset commands."

This reverts commit 53f0942e3d4a973a59729eb747c80af97479663f.
Add posix lock on all execute cmd.

This is required to prevent a race condition when 2 or more instances of the script running simultaneously could lead to a kernel EAGAIN message when managing iptables, ebtables, ipset rules. Such error is actually being ignored by the script