Execute build-pivotal-file commands in example dir
Execute build-pivotal-file commands in example dir

Fixes regression by refactor in previous commit:

```
ops-manager-example-repo/build-pivotal-file: line 46: example-release/build-release-tarball: No such file or directory
```

Signed-off-by: Erñesto Dunlap <329c7d75de881b58d3d971dc02fa4530c06ae3cb@pivotal.io>

pivotal-cf-experimental/ops-manager-example,pivotal-cf-experimental/ops-manager-example,pivotal-cf-experimental/ops-manager-example,pivotal-cf-experimental/ops-manager-example