aa174316

By: Tom Sydney Kerckhove <syd@cs-syd.eu>

ical-recurrence: test the ambiguous side of a daylight saving transition

Ignoring an instance whose local time does not exist and choosing between
the two readings of one that happens twice are the same code path.  The
ambiguous side already behaves sensibly by taking the earlier offset, so
pin it before changing the other side.