In case of redistricting or division of such city into wards, creation of any new ward or wards, or change of boundary in any ward or wards, every qualified elector residing in any ward at any general city election next thereafter, duly registered, shall be a qualified voter of such ward, and nothing in this chapter contained shall be so construed as to prevent any elector from voting or being eligible to any office by reason merely of such redistricting or division or creation of any new ward or wards, or change in the boundary of any ward or wards.