do not delete data dir for in-place import

src/backups.js

@@ -14,7 +14,7 @@ exports = module.exports = {
     restore: restore,
 
     backupApp: backupApp,
-    restoreApp: restoreApp,
+    downloadApp: downloadApp,
 
     backupBoxAndApps: backupBoxAndApps,
 
@@ -651,19 +651,12 @@ function restore(backupConfig, backupId, progressCallback, callback) {
     });
 }
 
-function restoreApp(app, addonsToRestore, restoreConfig, progressCallback, callback) {
+function downloadApp(app, restoreConfig, progressCallback, callback) {
     assert.strictEqual(typeof app, 'object');
-    assert.strictEqual(typeof addonsToRestore, 'object');
     assert.strictEqual(typeof restoreConfig, 'object');
     assert.strictEqual(typeof progressCallback, 'function');
     assert.strictEqual(typeof callback, 'function');
 
-    if (!restoreConfig.backupId) { // in-place import
-        debug('restoreApp: in-place import');
-
-        return addons.restoreAddons(app, addonsToRestore, callback);
-    }
-
     const appDataDir = safe.fs.realpathSync(path.join(paths.APPS_DATA_DIR, app.id));
     if (!appDataDir) return callback(safe.error);
     const dataLayout = new DataLayout(appDataDir, app.dataDir ? [{ localDir: app.dataDir, remoteDir: 'data' }] : []);
@@ -674,11 +667,8 @@ function restoreApp(app, addonsToRestore, restoreConfig, progressCallback, callb
     getBackupConfigFunc(function (error, backupConfig) {
         if (error) return callback(error);
 
-        async.series([
-            download.bind(null, backupConfig, restoreConfig.backupId, restoreConfig.backupFormat, dataLayout, progressCallback),
-            addons.restoreAddons.bind(null, app, addonsToRestore)
-        ], function (error) {
-            debug('restoreApp: time: %s', (new Date() - startTime)/1000);
+        download(backupConfig, restoreConfig.backupId, restoreConfig.backupFormat, dataLayout, progressCallback, function (error) {
+            debug('downloadApp: time: %s', (new Date() - startTime)/1000);
 
             callback(error);
         });