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)