Get settings.py through django.conf

The previous "from webodm import settings"  would get the first settings.py
Using django.conf is a better option 
This is discussed in this Stack Overflow topic: https://stackoverflow.com/questions/19976115/whats-the-difference-between-from-django-conf-import-settings-and-import-set
And in the docs: https://docs.djangoproject.com/en/dev/topics/settings/#using-settings-in-python-code

app/plugins/functions.py

@@ -14,7 +14,7 @@ from django.http import HttpResponse
 
 from app.models import Plugin
 from app.models import Setting
-from webodm import settings
+from django.conf import settings
 
 logger = logging.getLogger('app.logger')
 
@@ -306,4 +306,4 @@ def versionToInt(version):
     try:
         return sum([reduce(lambda mult, ver: mult * ver, i) for i in zip([100000, 100, 1], map(int, version.split(".")))])
     except:
-        return -1
+        return -1