TabBar: fix a typo
TabBar: fix a typo

Task-number: QTBUG-38819
Change-Id: I2ca82e5f5aa64f515225f7da262adb4d9b239802
Reviewed-by: Gabriel de Dietrich <57b5c683f0b6abfc17ef151d5b68c8944258b63a@digia.com>

mizukusak/qtquickcontrols,mizukusak/qtquickcontrols,mizukusak/qtquickcontrols