Fix duplicate shift state change when focus object changes

Previously the shift state could be set twice when focus object changed,
first in reset() method and then in autoCapitalize() method.

This change eliminates the initial shift state in reset() method.

Task-number: QTBUG-57082
Change-Id: I4bba5c85aae1d0d631e7e30577d0d4068c9cc582
Reviewed-by: Mitch Curtis <mitch.curtis@qt.io>