Update to 1.4.9, bump ABI depends as usual for this package.

Changes in 1.4.9-stable:
o event_add would not return error for some backends; from Dean
McNamee
o Clear the timer cache on entering the event loop; reported by
Victor Chang
o Only bind the socket on connect when a local address has been
provided; reported by Alejo Sanchez
o Allow setting of local port for evhttp connections to support
millions of connections from a single system; from Richard Jones.
o Clear the timer cache when leaving the event loop; reported by
Robin Haberkorn
o Fix a typo in setting the global event base; reported by lance.
o Fix a memory leak when reading multi-line headers
o Fix a memory leak by not running explicit close detection for
server connections

(wiz)