Adapt to new fdio location following http://fxrev.dev/399610

Change-Id: I43636cc14c4bef4e708211e00209e833d07fc93c
Reviewed-on: https://fuchsia-review.googlesource.com/c/fargo/+/414620
Reviewed-by: Rob Tsuk <robtsuk@google.com>
diff --git a/src/package.rs b/src/package.rs
index 1d099dc..eecc2ac 100644
--- a/src/package.rs
+++ b/src/package.rs
@@ -128,11 +128,7 @@
         zircon_build.to_string_lossy(),
         target_options.config.fuchsia_arch
     );
-    let fdio_path = format!(
-        "{}/user-{}-clang.shlib/obj/system/ulib/fdio/libfdio.so",
-        zircon_build.to_string_lossy(),
-        target_options.config.fuchsia_arch
-    );
+    let fdio_path = format!("{}/libfdio.so", shared_lib_str);
     let libsyslog_path = format!("{}/libsyslog.so", shared_lib_str);
     let libtraceengine_path = format!("{}/libtrace-engine.so", shared_lib_str);
     let libasync_path = format!("{}/libasync-default.so", shared_lib_str);