[1.7.x] Fixed several typos in Django

Backport of 1dcc603eff from master

tests/admin_views/admin.py

@@ -216,7 +216,7 @@ class SubscriberAdmin(admin.ModelAdmin):
     def mail_admin(self, request, selected):
         EmailMessage(
             'Greetings from a ModelAdmin action',
-            'This is the test email from a admin action',
+            'This is the test email from an admin action',
             'from@example.com',
             ['to@example.com']
         ).send()