CVE-2024-26634 net: fix removing a namespace with conflicting altnames

In the Linux kernel, the following vulnerability has been resolved:

net: fix removing a namespace with conflicting altnames

Mark reports a BUG() when a net namespace is removed.

kernel BUG at net/core/dev.c:11520!

Physical interfaces moved outside of init_net get “refunded”
to init_net when that namespace disappears. The main interface
name may get overwritten in the process if it would have
conflicted. We need to also discard all conflicting altnames.
Recent fixes addressed ensuring that altnames get moved
with the main interface, which surfaced this problem.