[Backport to 11.0] CMS time zone should be shown in the error message for scheduled publication/de-publication

Steps to reproduce:

1. Change CMS time zone to NZ-CHAT time zone which is almost 10:45 minutes ahead of Amsterdam time.
2. Go to news->2014->10 and select "Kosvo independence ruled by" document.
3. Try to "schedule take Offline" option.
4. Notice in the Publication end on shows the CMS set time zone.Which is correct.
5. Now change the minutes and set it to 10 minutes before the current time(i.e current time of CMS time not the OS time)
6. Click Ok button.
7. Error is shown but the time in the error is incorrect.

Expected: CMS time zone time should be shown in the error message & not the OS timezone.
Actual: OS time zone is shown.
Same is applicable for scheduled publication