Revert "aix: replace ECONNRESET with EOF if already closed"

This reverts commit ca08b48252, for the
same reasons that it was reverted the last time it was merged.

Refs: https://github.com/libuv/libuv/pull/475
Refs: https://github.com/libuv/libuv/pull/2447
PR-URL: https://github.com/libuv/libuv/pull/2602
Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>
Reviewed-By: Michael Dawson <michael_dawson@ca.ibm.com>

src/unix/stream.c

@@ -1185,10 +1185,6 @@ static void uv__read(uv_stream_t* stream) {
       } else if (errno == ECONNRESET && stream->type == UV_NAMED_PIPE) {
         uv__stream_eof(stream, &buf);
         return;
-#elif defined(_AIX)
-      } else if (errno == ECONNRESET && (stream->flags & UV_DISCONNECT)) {
-        uv__stream_eof(stream, &buf);
-        return;
 #endif
       } else {
         /* Error. User should call uv_close(). */