finatra-examples: Disable SBT Build for HelloWorldHeroku Example
finatra-examples: Disable SBT Build for HelloWorldHeroku Example

Summary: Problem / Solution

The HelloWorldHeroku Finatra example depends on the `finagle-metrics`
library. With changes for Stats verbosity, the `finagle-metrics`
library is no longer binary compatible with the current version of
Finatra. This disables this example for now, until CSL publishes `util`
and `finagle`, and `finagle-metrics` has been updated to use this new
compatible version.

JIRA Issues: CSL-5008

Differential Revision: https://phabricator.twitter.biz/D79311

twitter/finatra,twitter/finatra,twitter/finatra