curl_easy_recv.3: CURLINFO_LASTSOCKET => CURLINFO_ACTIVESOCKET

Closes #479

docs/libcurl/curl_easy_recv.3

@@ -49,7 +49,7 @@ this option.
 You must ensure that the socket has data to read before calling
 \fIcurl_easy_recv(3)\fP, otherwise the call will return \fBCURLE_AGAIN\fP -
 the socket is used in non-blocking mode internally. Use
-\fIcurl_easy_getinfo(3)\fP with \fBCURLINFO_LASTSOCKET\fP to obtain the
+\fIcurl_easy_getinfo(3)\fP with \fBCURLINFO_ACTIVESOCKET(3)\fP to obtain the
 socket; use your operating system facilities like \fIselect(2)\fP to check if
 it has any data you can read.
 .SH AVAILABILITY