PEP8 cleanups, remove OCR_CACHE_URI

apps/ocr/exceptions.py

@@ -1,21 +1,21 @@
 class AlreadyQueued(Exception):
-    '''
+    """
     Raised when a trying to queue document already in the queue
-    '''    
+    """
     pass
 
 
 class TesseractError(Exception):
-    '''
+    """
     Raised by tesseract
-    '''    
+    """
     pass
 
 
 class UnpaperError(Exception):
-    '''
+    """
     Raised by unpaper
-    '''
+    """
     pass