Use unwrap_or_else instead of expect

Clippy emits:

  warning: use of `expect` followed by a function call

As suggested, use `unwrap_or_else` with `panic!`.

bitcoind-tests/tests/test_cpp.rs

@@ -215,7 +215,7 @@ pub fn test_from_cpp_ms(cl: &Client, testdata: &TestData) {
             // Check whether the node accepts the transactions
             let txid = cl
                 .send_raw_transaction(&tx)
-                .expect(&format!("{} send tx failed for ms {}", i, ms));
+                .unwrap_or_else(|_| panic!("{} send tx failed for ms {}", i, ms));
             spend_txids.push(txid);
         }
     }

bitcoind-tests/tests/test_desc.rs

@@ -286,7 +286,7 @@ pub fn test_desc_satisfy(
     // Check whether the node accepts the transactions
     let txid = cl
         .send_raw_transaction(&tx)
-        .expect(&format!("send tx failed for desc {}", definite_desc));
+        .unwrap_or_else(|_| panic!("send tx failed for desc {}", definite_desc));
 
     // Finally mine the blocks and await confirmations
     let _blocks = cl