default.xml: Bump meta-virtualization revision

* 33eec78 : ceph: upgrade v15.2.15 -> v15.2.17 - sakib.sajal@windriver.com
* 406eb64 : singularity: Drop explicit runtime dep glibc - Andrei Gherzan

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