Improve setting dump serialization.

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

mayan/apps/smart_settings/forms.py

@@ -3,11 +3,7 @@ from __future__ import unicode_literals
 import yaml
 
 from django import forms
-from django.conf import settings
-from django.contrib.auth import get_user_model
 from django.core.exceptions import ValidationError
-from django.db import models
-from django.utils.module_loading import import_string
 from django.utils.translation import ugettext_lazy as _
 
 
@@ -20,11 +16,11 @@ class SettingForm(forms.Form):
     def __init__(self, *args, **kwargs):
         super(SettingForm, self).__init__(*args, **kwargs)
         self.fields['value'].help_text = self.initial['setting'].help_text
-        self.fields['value'].initial = self.initial['setting'].value
+        self.fields['value'].initial = self.initial['setting'].serialized_value
 
     def clean(self):
         try:
-            yaml.safe_dump(self.cleaned_data['value'])
+            yaml.safe_load(self.cleaned_data['value'])
         except yaml.YAMLError as exception:
             try:
                 yaml.safe_load('{}'.format(self.cleaned_data['value']))