do turnstile step only if blockchain is not syncing

src/turnstile.cpp

@@ -247,6 +247,10 @@ ProgressReport Turnstile::getPlanProgress() {
 }
 
 void Turnstile::executeMigrationStep() {
+    // Do a step only if not syncing, else wait for the blockchain to catch up
+    if (Settings::getInstance()->isSyncing())
+        return;
+
     auto plan = readMigrationPlan();
 
     //qDebug() << QString("Executing step");