Revert "Skip app/vendors from compilemessages #763" (#768)

This reverts commit 0af534c.

--ignore option for compilemessages is supported in greater than django 3.0.
https://docs.djangoproject.com/en/3.1/ref/django-admin/#cmdoption-compilemessages-ignore

makemessages support --ignore even on django 1.x
https://docs.djangoproject.com/en/3.1/ref/django-admin/#cmdoption-makemessages-ignore

Indeed, our django version is 1.11.29, which is the last version for Python 2.x
Django 1.11 is the last version to support Python 2.7. Support for Python 2.7 and Django 1.11 ends in 2020.
https://docs.djangoproject.com/en/3.1/faq/install/

tools/update_messages.py

@@ -189,5 +189,4 @@ def django_admin(*args):
 
     # Run compilemessages to generate all the .mo files.
     sys.stderr = open('/dev/null', 'w')  # suppress the listing of all files
-    django_admin('compilemessages',
-                 '--ignore=vendors')
+    django_admin('compilemessages')