ledflasher: Use helper Command::AbortWithCustomError() method

weaved now provides new variants of Command::Abort() that allow
to specify the error information as brillo::Error or binder::Status.

BUG: 25875613
Change-Id: Icf82c1c6c752eae7e651213d46e42baa103bef38

src/ledflasher/ledflasher.cpp

@@ -156,8 +156,7 @@ void Daemon::OnSet(std::unique_ptr<weaved::Command> command) {
   bool on = command->GetParameter<bool>("on");
   android::binder::Status status = led_service_->setLED(index - 1, on);
   if (!status.isOk()) {
-    command->Abort("_system_error", status.exceptionMessage().string(),
-                   nullptr);
+    command->AbortWithCustomError(status, nullptr);
     return;
   }
   animation_.reset();
@@ -183,8 +182,7 @@ void Daemon::OnToggle(std::unique_ptr<weaved::Command> command) {
   if (status.isOk())
     status = led_service_->setLED(index, !on);
   if(!status.isOk()) {
-    command->Abort("_system_error", status.exceptionMessage().string(),
-                   nullptr);
+    command->AbortWithCustomError(status, nullptr);
     return;
   }
   animation_.reset();