Remove socket from socket_class_set

It seems socket is not used as a security class any longer, just as a
common prefix which is then inherited by particular socket classes.

policy/modules/kernel/domain.te

@@ -267,7 +267,7 @@ allow unconfined_domain_type self:lnk_file setattr;
 
 # Use/sendto/connectto sockets created by any domain.
 allow unconfined_domain_type self:cap_userns all_cap_userns_perms;
-allow unconfined_domain_type domain:{ socket_class_set socket } *;
+allow unconfined_domain_type domain:socket_class_set *;
 
 allow unconfined_domain_type domain:system all_system_perms;
 # Use descriptors and pipes created by any domain.