WASHINGTON — Facing a growing backlash over extremely long airport security lines, Homeland Security Secretary Jeh Johnson today asked fliers “to be patient” as the government takes steps to get them onto planes more quickly.Travelers across the country have endured lengthy lines, some snaking up and down escalators, or through food courts, and into terminal lobbies. At some airports, lines during peak hours have topped 90 minutes. Airlines have reported holding planes at gates to wait for passengers to …