Use timezone in exception ics files

* Exchange seems to require time zone information in ics files containing
  event exceptions, although this is NOT the case for iCalendar, and appears
  not to conform to VCALENDAR specifications
* This causes exceptions to be placed on the wrong date or perhaps even
  ignored, depending on the circumstance
* This CL simply adds time zone information to all exception ics files

Bug: 2640878
Change-Id: Ibc614eb7a2c45e9e782b10be979d9892bbfc0029
1 file changed