Revert "ikhal: cannot focus empty eventlist anymore"

This reverts commit 27cff0b3c1f907da5b4ad9b98f4994c38ec4527f.
ikhal: cannot focus empty eventlist anymore (again)

Much nicer solution than before, without a bug that would prevent the
focus to move to the right column on pressing 'n' with no previous event
on that date.