[fractal] fractal-matrix-api: Drop redundant closures

[Alexandre Franke <afranke src gnome org>]

commit 4d34eed4aba1d9da662f5ce05614dec57feaab45
Author: Zeeshan Ali <zeenix collabora co uk>
Date:   Mon Dec 10 17:15:41 2018 +0100

    fractal-matrix-api: Drop redundant closures
    
    Fixing clippy error:
    
    ```
    error: redundant closure found
       --> fractal-matrix-api/src/util.rs:219:60
        |
    219 |         r.prev_batch = timeline["prev_batch"].as_str().map(|s| String::from(s));
        |                                                            ^^^^^^^^^^^^^^^^^^^ help: remove closure 
as shown: `String::from`
        |
        = note: `-D clippy::redundant-closure` implied by `-D warnings`
        = help: for further information visit 
https://rust-lang-nursery.github.io/rust-clippy/master/index.html#redundant_closure
    ```
    
    Related: #370

 fractal-matrix-api/src/backend/room.rs  | 2 +-
 fractal-matrix-api/src/model/message.rs | 4 ++--
 fractal-matrix-api/src/util.rs          | 2 +-
 3 files changed, 4 insertions(+), 4 deletions(-)
---
diff --git a/fractal-matrix-api/src/backend/room.rs b/fractal-matrix-api/src/backend/room.rs
index c3c0af8..911e2b0 100644
--- a/fractal-matrix-api/src/backend/room.rs
+++ b/fractal-matrix-api/src/backend/room.rs
@@ -140,7 +140,7 @@ pub fn get_room_messages(bk: &Backend, roomid: String, from: String) -> Result<(
             let array = r["chunk"].as_array();
             let evs = array.unwrap().iter().rev();
             let list = Message::from_json_events_iter(roomid.clone(), evs);
-            let prev_batch = r["end"].as_str().map(|s| String::from(s));
+            let prev_batch = r["end"].as_str().map(String::from);
             tx.send(BKResponse::RoomMessagesTo(list, roomid, prev_batch))
                 .unwrap();
         },
diff --git a/fractal-matrix-api/src/model/message.rs b/fractal-matrix-api/src/model/message.rs
index d50c735..2a7bc94 100644
--- a/fractal-matrix-api/src/model/message.rs
+++ b/fractal-matrix-api/src/model/message.rs
@@ -152,8 +152,8 @@ impl Message {
     fn parse_m_room_message(msg: &mut Message, c: &JsonValue) {
         let mtype = c["msgtype"].as_str().unwrap_or("");
         let body = c["body"].as_str().unwrap_or("");
-        let formatted_body = c["formatted_body"].as_str().map(|s| String::from(s));
-        let format = c["format"].as_str().map(|s| String::from(s));
+        let formatted_body = c["formatted_body"].as_str().map(String::from);
+        let format = c["format"].as_str().map(String::from);
 
         match mtype {
             "m.image" | "m.file" | "m.video" | "m.audio" => {
diff --git a/fractal-matrix-api/src/util.rs b/fractal-matrix-api/src/util.rs
index 07cffed..42b270a 100644
--- a/fractal-matrix-api/src/util.rs
+++ b/fractal-matrix-api/src/util.rs
@@ -216,7 +216,7 @@ pub fn get_rooms_from_json(r: &JsonValue, userid: &str, baseu: &Url) -> Result<V
             .as_i64()
             .unwrap_or(0) as i32;
 
-        r.prev_batch = timeline["prev_batch"].as_str().map(|s| String::from(s));
+        r.prev_batch = timeline["prev_batch"].as_str().map(String::from);
 
         if let Some(ev) = dataevs.as_array() {
             for tag in ev.iter().filter(|x| x["type"] == "m.tag") {