[mod_ssi] fix "ssi_val_init" prototype

From: Stefan Bühler <stbuehler@web.de>

git-svn-id: svn://svn.lighttpd.net/lighttpd/branches/lighttpd-1.4.x@2924 152afb58-edef-0310-8abb-c4023f1b3aa9
[ssl] fix regression from CVE-2013-4508 (client-cert sessions were broken)

From: Stefan Bühler <stbuehler@web.de>

git-svn-id: svn://svn.lighttpd.net/lighttpd/branches/lighttpd-1.4.x@2925 152afb58-edef-0310-8abb-c4023f1b3aa9