Fix fuchsia-zircon dependency

Change-Id: Id51a4ac786bd3eb31caa1b67fed56e805549a437
diff --git a/Cargo.toml b/Cargo.toml
index c24b8a2..083b10d 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -29,7 +29,7 @@
 iovec    = "0.1.1"
 
 [target.'cfg(target_os = "fuchsia")'.dependencies]
-fuchsia-zircon = { path = "../../../garnet/public/rust/crates/fuchsia-zircon" }
+fuchsia-zircon = "0.3"
 
 [target.'cfg(unix)'.dependencies]
 libc   = "0.2.19"