net: fix leak of fd in bind() error path

Signed-off-by: Jens Axboe <axboe@fb.com>
diff --git a/engines/net.c b/engines/net.c
index fcf4b89..d036a58 100644
--- a/engines/net.c
+++ b/engines/net.c
@@ -1092,6 +1092,7 @@
 	}
 
 	if (bind(fd, saddr, len) < 0) {
+		close(fd);
 		td_verror(td, errno, "bind");
 		return 1;
 	}