Check mLocalFolder nullability in RefreshFolderOperation.java

Signed-off-by: alperozturk <alper_ozturk@proton.me>

app/src/main/java/com/owncloud/android/operations/RefreshFolderOperation.java

@@ -453,6 +453,11 @@ public class RefreshFolderOperation extends RemoteOperation {
         // get 'fresh data' from the database
         mLocalFolder = mStorageManager.getFileByPath(mLocalFolder.getRemotePath());
 
+        if (mLocalFolder == null) {
+            Log_OC.d(TAG,"mLocalFolder cannot be null");
+            return;
+        }
+
         // parse data from remote folder
         OCFile remoteFolder = FileStorageUtils.fillOCFile((RemoteFile) folderAndFiles.get(0));
         remoteFolder.setParentId(mLocalFolder.getParentId());