Initialize PyOCR backend tool attribute to a sane default.

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

mayan/apps/ocr/backends/pyocr.py

@@ -16,18 +16,19 @@ class PyOCR(OCRBackendBase):
     def __init__(self, *args, **kwargs):
         super(PyOCR, self).__init__(*args, **kwargs)
 
+        self.languages = ()
+
         tools = pyocr.get_available_tools()
         if len(tools) == 0:
             raise OCRError('No OCR tool found')
 
+        self.tool = tools[0]
+
         # The tools are returned in the recommended order of usage
         for tool in tools:
             if tool.__name__ == 'pyocr.libtesseract':
                 self.tool = tool
 
-        if not self.tool:
-            self.tool = tools[0]
-
         logger.debug('Will use tool \'%s\'', self.tool.get_name())
 
         self.languages = self.tool.get_available_languages()