[1.7.x] Fixed #23283 -- Added default=False to BooleanField's in the docs.

Thanks Baptiste for the suggestion.

Backport of 6947885926 from master

docs/releases/1.7.txt

@@ -185,7 +185,7 @@ class method can now directly :ref:`create Manager with QuerySet methods
 
     class Food(models.Model):
         kind = models.CharField(max_length=50)
-        vegetarian = models.BooleanField()
+        vegetarian = models.BooleanField(default=False)
         objects = FoodQuerySet.as_manager()
 
     Food.objects.pizzas().vegetarian()

docs/topics/db/examples/one_to_one.txt

@@ -21,8 +21,8 @@ In this example, a ``Place`` optionally can be a ``Restaurant``:
 
     class Restaurant(models.Model):
         place = models.OneToOneField(Place, primary_key=True)
-        serves_hot_dogs = models.BooleanField()
-        serves_pizza = models.BooleanField()
+        serves_hot_dogs = models.BooleanField(default=False)
+        serves_pizza = models.BooleanField(default=False)
 
         def __str__(self):              # __unicode__ on Python 2
             return "%s the restaurant" % self.place.name

docs/topics/db/models.txt

@@ -1005,8 +1005,8 @@ For example::
         address = models.CharField(max_length=80)
 
     class Restaurant(Place):
-        serves_hot_dogs = models.BooleanField()
-        serves_pizza = models.BooleanField()
+        serves_hot_dogs = models.BooleanField(default=False)
+        serves_pizza = models.BooleanField(default=False)
 
 All of the fields of ``Place`` will also be available in ``Restaurant``,
 although the data will reside in a different database table. So these are both

docs/topics/serialization.txt

@@ -84,7 +84,7 @@ model will be serialized. For example, consider the following models::
         name = models.CharField(max_length=50)
 
     class Restaurant(Place):
-        serves_hot_dogs = models.BooleanField()
+        serves_hot_dogs = models.BooleanField(default=False)
 
 If you only serialize the Restaurant model::