fix deadlock while adding new addresses

lib/src/lightclient.rs

@@ -827,9 +827,10 @@ impl LightClient {
             return Err("Wallet is locked".to_string());
         }
 
+        let new_address = {
             let wallet = self.wallet.write().unwrap();
 
-        let new_address = match addr_type {
+            match addr_type {
                 "z" => wallet.add_zaddr(),
                 "t" => wallet.add_taddr(),
                 _   => {
@@ -837,6 +838,7 @@ impl LightClient {
                     error!("{}", e);
                     return Err(e);
                 }
+            }
         };
 
         self.do_save()?;