lock: Decrease the number of iterations per second

lock: Decrease the number of iterations per second

There have been reports about that this locking mechanism
wasn't too stable on their machines which can totally be
the case judging by the design of it.

However there is no other easy way to implement this any
better without any native C helper which I would like to
avoid at this moment.

So I decreased the amount of ticks which should make
any processes running at the same time less likely to
collide.

Fixes #10979

Signed-off-by: Michael Tremer <michael.tremer@ipfire.org>