Fix google crash

Close e/backlog#4173 (closed)

How to test

⚠ Note, this tests were made using a timeout of 300 seconds ("timeout: 300" under "- name : google images" on the file searx/settings.yml), because locally it takes some time to load things

1. Run sudo make run
2. Go to http://localhost/preferences
3. Disable all search engines under "images" and only enable Google images
4. Search for anything
5. Go to images
6. Assert that you can see the images
7. Assert that no crash from google images appears on the logs