Delete the default network created by the project. (hashicorp#1316)

docs/r/google_project.html.markdown

@@ -97,6 +97,11 @@ The following arguments are supported:
 
 * `labels` - (Optional) A set of key/value label pairs to assign to the project.
 
+* `auto_create_network` - (Optional) Create the 'default' network automatically.  Default true.
+    Note: this might be more accurately described as "Delete Default Network", since the network
+    is created automatically then deleted before project creation returns, but we choose this
+    name to match the GCP Console UI.
+
 ## Attributes Reference
 
 In addition to the arguments listed above, the following computed attributes are