transport-helper: drop read/write errno checks

Since we use xread() and xwrite() here, EINTR, EAGAIN, and
EWOULDBLOCK retries are already handled for us, and we will
never see these errno values ourselves. We can drop these
conditions entirely, making the code easier to follow.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

transport-helper.c

@@ -1226,8 +1226,7 @@ static int udt_do_read(struct unidirectional_transfer *t)
 
 	transfer_debug("%s is readable", t->src_name);
 	bytes = xread(t->src, t->buf + t->bufuse, BUFFERSIZE - t->bufuse);
-	if (bytes < 0 && errno != EWOULDBLOCK && errno != EAGAIN &&
-		errno != EINTR) {
+	if (bytes < 0) {
 		error_errno(_("read(%s) failed"), t->src_name);
 		return -1;
 	} else if (bytes == 0) {
@@ -1254,7 +1253,7 @@ static int udt_do_write(struct unidirectional_transfer *t)
 
 	transfer_debug("%s is writable", t->dest_name);
 	bytes = xwrite(t->dest, t->buf, t->bufuse);
-	if (bytes < 0 && errno != EWOULDBLOCK) {
+	if (bytes < 0) {
 		error_errno(_("write(%s) failed"), t->dest_name);
 		return -1;
 	} else if (bytes > 0) {