access-control/tfa: use ? instead of unnecessary match statements

this makes the code more concise and legible. fixes a clippy lint [1].

[1]:
https://rust-lang.github.io/rust-clippy/master/index.html#question_mark

Signed-off-by: Shannon Sterz <s.sterz@proxmox.com>

proxmox-access-control/src/acl.rs

@@ -208,10 +208,7 @@ impl AclTree {
         let mut node = &self.root;
         for outer in path {
             for comp in outer.split('/') {
-                node = match node.children.get(comp) {
-                    Some(n) => n,
-                    None => return None,
-                };
+                node = node.children.get(comp)?;
             }
         }
         Some(node)
@@ -221,10 +218,7 @@ impl AclTree {
         let mut node = &mut self.root;
         for outer in path {
             for comp in outer.split('/') {
-                node = match node.children.get_mut(comp) {
-                    Some(n) => n,
-                    None => return None,
-                };
+                node = node.children.get_mut(comp)?;
             }
         }
         Some(node)

proxmox-tfa/src/api/methods.rs

@@ -98,10 +98,7 @@ pub fn list_user_tfa(config: &TfaConfig, userid: &str) -> Result<Vec<TypedTfaInf
 ///
 /// In case this returns `None` a `NOT_FOUND` http error should be returned.
 pub fn get_tfa_entry(config: &TfaConfig, userid: &str, id: &str) -> Option<TypedTfaInfo> {
-    let user_data = match config.users.get(userid) {
-        Some(u) => u,
-        None => return None,
-    };
+    let user_data = config.users.get(userid)?;
 
     Some({
         let res = {