Remove the recursive delete of triggers.

[JadeRedworth]

[https://github.com/fnproject/cli/issues/598](Recursive delete checks for triggers that are no longer supports)

The following command fn delete app <app-name> -r tries to list functions and triggers to perform a recursive delete. The response we give back is:

Fn: Failed to get associated objects: Could not list triggers in function : [GET /triggers][404] ListTriggers default &{Fields: Message:HTTP Triggers are not supported on Oracle Functions.}.

I have removed the check for triggers on both delete app and delete function.