In case a temporary vacancy is created in any office or position by reason of the absence of the officer in the military service the appointive authority shall appoint some person to fill temporarily the office or position to which such officer was elected or appointed. All such appointees shall hold the office or position which they are temporarily to fill during the absence of the officer in the military service or until the expiration of the term for which such officer in the military service was elected or appointed, whichever period of time is the shorter.