xfer: Fix xfer.network.own_ip behavior

Fixes #5. xfer shouldn't try to bind() to the own_ip
address. Instead, always bind to the same local address that is
connected to the irc server, and just change the out_addr if own_ip is
used.

Also fixes a memory leak in error path.
Merge branch 'master' of git://github.com/talisein/weechat-1 into talisein-master