default.xml: Bump meta-security revision

* c79262a : meta-integrity: kernel-modsign: prevents splitting out debug symbols - Jose Quaresma
* e54e064 : clamav: make install owner match the added user name - Jeremy A. Puhlman
* c29ef97 : python3-privacyidea: add correct path to lib/privacyidea - Jeremy A. Puhlman
* ab90048 : libmhash: add multilib header - Jeremy A. Puhlman
* 7e3596e : sssd: ignore CVE-2018-16838 - Davide Gardenal

Signed-off-by: Pavel Zhukov <pavel.zhukov@huawei.com>