lib/osutil: Fix raising max FDs on macOS (#7507)
lib/osutil: Fix raising max FDs on macOS (#7507)

There was a logic mistake, so the limit in question wasn't used. On my
macOS this doesn't seem to matter, the hard limit returned is 2^63-1 and
setting the soft limit to that works. However I'm assuming that's not
the case for older macOSes since it was so nicely documented, so we
should still have this working. (10240 FDs should be enough for
anybody.)
syncthing/syncthing,syncthing/syncthing,syncthing/syncthing,wweich/syncthing,wweich/syncthing,syncthing/syncthing,syncthing/syncthing,syncthing/syncthing,wweich/syncthing,wweich/syncthing