OCR: Update app to use document image cache

Update the OCR app to use the document image cache instead
of trying to read the image file directly from
the document storage.

Signed-off-by: Roberto Rosario <roberto.rosario.gonzalez@gmail.com>

mayan/apps/ocr/managers.py

@@ -8,7 +8,6 @@ from django.apps import apps
 from django.conf import settings
 from django.db import models
 
-from mayan.apps.documents.storages import storage_documentimagecache
 from mayan.apps.documents.literals import DOCUMENT_IMAGE_TASK_TIMEOUT
 from mayan.apps.documents.tasks import task_generate_document_page_image
 
@@ -38,7 +37,7 @@ class DocumentPageOCRContentManager(models.Manager):
 
         cache_filename = task.get(timeout=DOCUMENT_IMAGE_TASK_TIMEOUT)
 
-        with storage_documentimagecache.open(cache_filename) as file_object:
+        with document_page.cache_partition.get_file(filename=cache_filename).open() as file_object:
             document_page_content, created = DocumentPageOCRContent.objects.get_or_create(
                 document_page=document_page
             )