Backport configuration file improvements

Remove support for quoted entried. Support unquoted entries. Support
custom location for the config files.

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

mayan/apps/ocr/runtime.py

@@ -1,20 +1,9 @@
 from __future__ import unicode_literals
 
-import yaml
-
-try:
-    from yaml import CSafeLoader as SafeLoader
-except ImportError:
-    from yaml import SafeLoader
-
 from django.utils.module_loading import import_string
 
 from .settings import setting_ocr_backend, setting_ocr_backend_arguments
 
 ocr_backend = import_string(
     dotted_path=setting_ocr_backend.value
-)(
-    **yaml.load(
-        stream=setting_ocr_backend_arguments.value or '{}', Loader=SafeLoader
-    )
-)
+)(**setting_ocr_backend_arguments.value)