[fractal] API, Backend: replace Clone impl with derive

[Christopher Davis <christopherdavis src gnome org>]

commit fb77a4c163b71481bad690a241ffd018ac8a97f5
Author: Alejandro Domínguez <adomu net-c com>
Date:   Thu Aug 29 23:07:47 2019 +0200

    API, Backend: replace Clone impl with derive

 fractal-matrix-api/src/backend/types.rs | 13 +------------
 1 file changed, 1 insertion(+), 12 deletions(-)
---
diff --git a/fractal-matrix-api/src/backend/types.rs b/fractal-matrix-api/src/backend/types.rs
index afb66cb6..4cf5434a 100644
--- a/fractal-matrix-api/src/backend/types.rs
+++ b/fractal-matrix-api/src/backend/types.rs
@@ -199,6 +199,7 @@ pub struct BackendData {
     pub m_direct: HashMap<String, Vec<String>>,
 }
 
+#[derive(Clone)]
 pub struct Backend {
     pub tx: Sender<BKResponse>,
     pub data: Arc<Mutex<BackendData>>,
@@ -209,15 +210,3 @@ pub struct Backend {
     // semaphore to limit the number of threads downloading images
     pub limit_threads: Arc<(Mutex<u8>, Condvar)>,
 }
-
-impl Clone for Backend {
-    fn clone(&self) -> Backend {
-        Backend {
-            tx: self.tx.clone(),
-            data: self.data.clone(),
-            internal_tx: self.internal_tx.clone(),
-            user_info_cache: self.user_info_cache.clone(),
-            limit_threads: self.limit_threads.clone(),
-        }
-    }
-}