Merge lp://qastaging/~gary-wzl77/qtorganizer5-eds/fix_1445577 into lp://qastaging/qtorganizer5-eds

Reading the bug report I would say that the event is losing the timezone when edited. Is the app setting the correct timezone? If the app does not set the timezone the event will be handled as a Floating event.

Actually, there is no such a timezone settings in app. App just follows system timezone.

My Time & Date in system settings
Time zone:
Asia/Shangehai UTC+8

----Create an event (display correctly in weeklyview)
qml: event.name: Ttttt
qml: event.startDateTime: Fri Jul 24 07:00:00 2015 GMT+0800
qml: event.endDateTime: Fri Jul 24 08:00:00 2015 GMT+0800

----Edit an event with only name changed (wrong display and event backs x hours)
qml: event.name: Ttttt-edit
qml: event.startDateTime: Fri Jul 24 07:00:00 2015 GMT+0800
qml: event.endDateTime: Fri Jul 24 08:00:00 2015 GMT+0800

I check this issue today and find sth as following:
when user modify a event with start or end date time changed, issue wont' occur.
when user modify a event without start datetime and end date time changed, issue occurs.
Reason for this is if start and end date time are not changed when modification, the timeSpec is for these two datetime is Qt::TimeZone instead of Qt::UTC when parsing them, then
tz.id().constData() == "able/localtime" which cause timezone == null and empty for tzId after icaltimezone_get_builtin_timezone was called.
so finally event backs x(timezone) hours after e_cal_client_modify_objects called.

As I mentioned above, we follow system timezone and have no way to set timezone in qml.
The easy fix is if start & end datetime are not floating time, then we need to convert Local timezone to UTC time zone.
Please review latest MP.
Thanks

Could you resubmit this MR adding "https://code.launchpad.net/~renatofilho/qtorganizer5-eds/fix-1437305/+merge/261666" as Prerequisite Branch, it will make only your changes visible on the diff. And make it easy to review.

OK, I will delete this one later on and create another MP for review since I can't resubmit merge proposal in same branch.
Thanks.