php: upgrade to 5.5.24

5.5.24 has several CVE fixes, like CVE-2015-1351, CVE-2015-1352
5.5.23 has fixes for CVE-2015-2787, CVE-2015-2348 etc.

Update the LICENSE checksum, since the date in LICENSE is updated to 2015

Signed-off-by: Roy Li <rongqing.li@windriver.com>
Signed-off-by: Martin Jansa <Martin.Jansa@gmail.com>