Update to 0.074 of ZNC, enable c-ares

c-ares was new in 0.072, but was disabled in the Fedora package

Fix a possible crash if users are deleted while they have active DCC sockets. (r1575)

-- The folllowing other update that was new to upstream ZNC 0.074 was already backported to znc-0.072-3 in Fedora

Fix a regression due to (r1569): Webadmin was broken if the skins were accessed through an absolute path (=almost always). (r1574)