Section 6. Governor to appoint officers. The governor shall nominate and, by and with the consent of the senate, appoint all officers whose offices are established by this constitution, or which may be created by law, and whose appointment or election is not otherwise provided for. If during the recess of the senate, a vacancy occurs in any state or district office, the governor shall appoint some fit person to discharge the duties thereof until the next meeting of the senate, when he shall nominate some person to fill such office. If the office of a justice of the supreme or district court, secretary of state, state controller, state treasurer, attorney general, or superintendent of public instruction shall be vacated by death, resignation or otherwise, it shall be the duty of the governor to fill the same by appointment, as provided by law, and the appointee shall hold his office until his successor shall be selected and qualified in such manner as may be provided by law.