rpctest: Cleanup resources on failed setup.

This modifies the rpctest harness to call the TearDown function in the
SetUp error path.  This ensures any resources, such as temp directories,
that were created during setup before whatever the failure that caused
the error are properly cleaned up.

rpcserver_test.go

@@ -117,6 +117,13 @@ func TestMain(m *testing.M) {
 	// purposes.
 	if err := primaryHarness.SetUp(true, 25); err != nil {
 		fmt.Println("unable to setup test chain: ", err)
+
+		// Even though the harness was not fully setup, it still needs
+		// to be torn down to ensure all resources such as temp
+		// directories are cleaned up.  The error is intentionally
+		// ignored since this is already an error path and nothing else
+		// could be done about it anyways.
+		_ = primaryHarness.TearDown()
 		os.Exit(1)
 	}
 

rpctest/rpc_harness_test.go

@@ -501,6 +501,13 @@ func TestMain(m *testing.M) {
 	// purposes.
 	if err = mainHarness.SetUp(true, numMatureOutputs); err != nil {
 		fmt.Println("unable to setup test chain: ", err)
+
+		// Even though the harness was not fully setup, it still needs
+		// to be torn down to ensure all resources such as temp
+		// directories are cleaned up.  The error is intentionally
+		// ignored since this is already an error path and nothing else
+		// could be done about it anyways.
+		_ = mainHarness.TearDown()
 		os.Exit(1)
 	}