The primary election is June 18. The runoff primary is Aug. 27, and the general election is Nov. 5. OKLAHOMA CITY – Filing for federal and state offices is set for April 3-5 at the Capitol. Election Board Secretary Paul Ziriax expects between 250 and 300 candidates to file for the legislative, U.S. House and one Corporation Commission posts. All 101 House seats and 26 Senate posts will be up…