Backport r940273 by smartins from trunk to the 4.2 branch:
Backport r940273 by smartins from trunk to the 4.2 branch:

All day events lasting X days were being displayed as X-1.

When creating the event it's displayed right because koeventeditor already addDays(1), the problem was when
editing it again.

svn path=/branches/KDE/4.2/kdepim/; revision=941456

lefou/kdepim-noakonadi,lefou/kdepim-noakonadi,lefou/kdepim-noakonadi,lefou/kdepim-noakonadi,lefou/kdepim-noakonadi,lefou/kdepim-noakonadi