Update to pkg 1.2.3
Changes:

• Workaround a bug in bsd.*.mk on FreeBSD 8.x
• Fix a pkg repo segfault
• Document aliases in pkg.conf(5)
• Be more verbose when refusing a repository configuration file
• Sync libucl with upstream (bug fixes)
• Fix a fd leak in pkg repo
• Fix memory leaks due bad usage of libarchive