[packages] php5: upgrade to 5.4.23

This upgrades includes a fix for a memory corruption
in openssl_x509_parse() (CVE-2013-6420).

Signed-off-by: Michael Heimpold <mhei@heimpold.de>

git-svn-id: svn://svn.openwrt.org/openwrt/packages@39140 3c298f89-4303-0410-b956-a3cf2f4a3e73