Move clone.sh out of tests/rust

To avoid spurious diffs in Travis from the cached tests/rust directory.
diff --git a/tests/common/mod.rs b/tests/common/mod.rs
index 7dbbeec..80f8db1 100644
--- a/tests/common/mod.rs
+++ b/tests/common/mod.rs
@@ -116,7 +116,7 @@
 }
 
 pub fn clone_rust() {
-    let result = Command::new("tests/rust/clone.sh").status().unwrap();
+    let result = Command::new("tests/clone.sh").status().unwrap();
     println!("result: {}", result);
     assert!(result.success());
 }