Use bitcoind.stop..

Instead of `bitcoind.client.stop` as the former handles child processes
as well as rpc client connection

roles/tests-integration/tests/common/mod.rs

@@ -146,7 +146,7 @@ impl TemplateProvider {
     }
 
     fn stop(&self) {
-        let _ = self.bitcoind.client.stop().unwrap();
+        self.bitcoind.stop().expect("Failed to stop bitcoind");
     }
 
     fn generate_blocks(&self, n: u64) {