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/converter/backends/python.py

@@ -7,11 +7,6 @@ import shutil
 from PIL import Image
 import PyPDF2
 import sh
-import yaml
-try:
-    from yaml import CSafeLoader as SafeLoader
-except ImportError:
-    from yaml import SafeLoader
 
 from django.utils.encoding import force_text
 from django.utils.translation import ugettext_lazy as _
@@ -20,16 +15,14 @@ from mayan.apps.storage.utils import NamedTemporaryFile
 
 from ..classes import ConverterBase
 from ..exceptions import PageCountError
-from ..settings import setting_graphics_backend_config
+from ..settings import setting_graphics_backend_arguments
 
 from ..literals import (
     DEFAULT_PDFTOPPM_DPI, DEFAULT_PDFTOPPM_FORMAT, DEFAULT_PDFTOPPM_PATH,
     DEFAULT_PDFINFO_PATH
 )
 
-pdftoppm_path = yaml.load(
-    stream=setting_graphics_backend_config.value, Loader=SafeLoader
-).get(
+pdftoppm_path = setting_graphics_backend_arguments.value.get(
     'pdftoppm_path', DEFAULT_PDFTOPPM_PATH
 )
 
@@ -39,26 +32,20 @@ except sh.CommandNotFound:
     pdftoppm = None
 else:
     pdftoppm_format = '-{}'.format(
-        yaml.load(
-            stream=setting_graphics_backend_config.value, Loader=SafeLoader
-        ).get(
+        setting_graphics_backend_arguments.value.get(
             'pdftoppm_format', DEFAULT_PDFTOPPM_FORMAT
         )
     )
 
     pdftoppm_dpi = format(
-        yaml.load(
-            stream=setting_graphics_backend_config.value, Loader=SafeLoader
-        ).get(
+        setting_graphics_backend_arguments.value.get(
             'pdftoppm_dpi', DEFAULT_PDFTOPPM_DPI
         )
     )
 
     pdftoppm = pdftoppm.bake(pdftoppm_format, '-r', pdftoppm_dpi)
 
-pdfinfo_path = yaml.load(
-    stream=setting_graphics_backend_config.value, Loader=SafeLoader
-).get(
+pdfinfo_path = setting_graphics_backend_arguments.value.get(
     'pdfinfo_path', DEFAULT_PDFINFO_PATH
 )