System properties aren't actually checked for changes in reload logic

[Woodham]

Looking at this line: https://github.com/lviggiano/owner/blob/0f0bfac11139264c27820bbc9c030c7448d395b9/owner/src/main/java/org/aeonbits/owner/HotReloadLogic.java#L69

It looks like the intention was to check if the hash of all system properties had changed since the last check, but newHash is not actually updated and just uses the original cached version of the system properties.

I suspect it's missing props = system().getProperties(); above that line.