samples: update timer callback prototype
samples: update timer callback prototype

The socks5 proxy sample application was still using the old prototype
where timer callbacks take a second 'status' parameter but that was
removed in commit db2a9072 ("unix, windows: removed unused status
parameter") from March 2014.

PR-URL: https://github.com/libuv/libuv/pull/1250
Reviewed-By: Colin Ihrig <838f779c91673db29b8572ea3f54d191d3878ae2@gmail.com>
Reviewed-By: Saúl Ibarra Corretgé <8a7991f6950ea189abf159d6ec98d2fcc13dc5f6@gmail.com>

unknownbrackets/maxcso,unknownbrackets/maxcso,unknownbrackets/maxcso,unknownbrackets/maxcso,unknownbrackets/maxcso,unknownbrackets/maxcso,unknownbrackets/maxcso