pneigh/NLF_PROXY: should NLM_F_EXCL be honored?

Hi,

by sending RTM_NEWNEIGH with NLF_PROXY in the ndmsg, a new proxy entry
can be added.

The code path taken ignores NLM_F_EXCL, returning success, even if the
proxy entry does already exist. Is this intended behaviour?

Best Regards,
Christian Franke