remove workaround for firmware alarm
remove workaround for firmware alarm

This reverts ead0e. When this bug first showed up the firmware version
was reported as zero, but it later turns out vedirect-interface also
sends other wrong values sometimes. This is now fixed in
vedirect-interface, and the workaround which was harmless but is
nevertheless unneeded is now removed.

https://github.com/victronenergy/venus/issues/674

victronenergy/dbus-systemcalc-py