Bug description
The documentation (in multiple places) says there is a 15s timeout with requests by default. I can confirm that this is not functioning if it is intended -- in fact, I have requests that go over 60s just fine. There may not even be a real timeout in place.

Applying a VirutalService with a timeout works as expected.

Expected behavior
Documented default timeout is actually what's used. Not sure if this is a documentation issue or an Istio issue itself.

Steps to reproduce the bug

1. Make requests to a service with 20s+ response time with no request timeout overrides
2. Observe that the request completes successfully.

Version (include the output of istioctl version --remote and kubectl version)
Istio 1.1.3
Kubernetes 1.11.8

How was Istio installed?
Helm with basic settings

Environment where bug was observed (cloud vendor, OS, etc)
AWS / Kops