Merge #249: Remove redundant tmp file existence check in wallet integration test

7eb3702 Remove redundant tmp file existence check in wallet integration test (GideonBature)

Pull request description:

  This PR removes the redundant `if file_path.exists()` check before deleting a temporary file.

  As pointed out during review of `backupwallet` integration test [here](#247 (comment)), the check is unnecessary.

ACKs for top commit:
  tcharding:
    ACK 7eb3702

Tree-SHA512: d2731742b13fc5395d5f691e131db3008f9738117158ebb0ea2dd2782a647eaba17a5481e7d8875d139ddb1e514ea1cbd6186c7cf935f5adcb7522eee06dc40d

Author: tcharding

integration_test/tests/wallet.rs

@@ -69,10 +69,6 @@ fn wallet__backup_wallet() {
     let node = Node::with_wallet(Wallet::Default, &[]);
     let file_path = integration_test::random_tmp_file();
 
-    if file_path.exists() {
-        fs::remove_file(&file_path).expect("removefile");
-    }
-
     node.client.backup_wallet(&file_path).expect("backupwallet");
     assert!(file_path.exists(), "Backup file should exist at destination");
     assert!(file_path.is_file(), "Backup destination should be a file");