[AF_KEY]: Fix oops by converting to proc_net_*().

[AF_KEY]: Fix oops by converting to proc_net_*().

To make sure the procfs visibility occurs after the ->proc_fs ops are
setup, use proc_net_fops_create() and proc_net_remove().

This also fixes an OOPS after module unload in that the name string
for remove was wrong, so it wouldn't actually be removed.  That bug
was introduced by commit cab156b25f2cc0edf06e411939808b0680764d9d
("[KEY]: Clean up proc files creation a bit.")

Signed-off-by: David S. Miller <davem@davemloft.net>