[MCHANGES-359] announcement-mail in multi-module project

**[Daniel Kreutz](https://issues.apache.org/jira/secure/ViewProfile.jspa?name=dkreutz)** opened **[MCHANGES-359](https://issues.apache.org/jira/browse/MCHANGES-359?redirect=false)** and commented

Hi,
I am using the announcement-mail goal on a multi-module project. I'd like to send one mail for the whole project and not for every single module. So maven-changes-plugin is only configured at the parent pom. The parent pom is called with `-Dannouncement.runOnlyAtExecutionRoot=true`.
Goal announcement-generate works well, but with announcement-mail I get the following error:

```
[INFO] ------------------------------------------------------------------------
[INFO] Building Submodule 1.0.0-SNAPSHOT
[INFO] ------------------------------------------------------------------------
[INFO]
[INFO] >>> maven-changes-plugin:2.11:announcement-mail (default-cli) > :announcement-generate @ submodule >>>
[INFO]
[INFO] --- maven-changes-plugin:2.11:announcement-generate (announcement-generate) @ submodule ---
[INFO] Skipping the announcement generation in this project because it's not the Execution Root
[INFO]
[INFO] <<< maven-changes-plugin:2.11:announcement-mail (default-cli) < :announcement-generate @ submodule <<<
[INFO]
[INFO] --- maven-changes-plugin:2.11:announcement-mail (default-cli) @ submodule ---
[INFO] ------------------------------------------------------------------------
[INFO] Reactor Summary:
[INFO]
[INFO] Submodule .................... FAILURE [ 0.784 s]
[INFO] Parent ........................... SUCCESS [ 24.840 s]
[INFO] ------------------------------------------------------------------------
[INFO] BUILD FAILURE
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 26.711 s
[INFO] Finished at: 2015-09-15T11:27:36+02:00
[INFO] Final Memory: 22M/218M
[INFO] ------------------------------------------------------------------------
[ERROR] Failed to execute goal org.apache.maven.plugins:maven-changes-plugin:2.11:announcement-mail (default-cli) on project submodule: The parameters 'toAddresses' for goal org.apache.maven.plugins:maven-changes-plugin:2.11:announcement-mail are missing or invalid -> [Help 1]
```

I suppose, `toAddresses` will be injected before runOnlyAtExecutionRoot is checked. So I get that error.

---

**Affects:** 2.11

**Attachments:**
- [MCHANGES-359.zip](https://issues.apache.org/jira/secure/attachment/12756434/MCHANGES-359.zip) (_5.58 kB_)

Start by reproducing the attached MCHANGES-359.zip project with the announcement-mail goal and runOnlyAtExecutionRoot=true. Compare the announcement-mail and announcement-generate execution paths; done means a multi-module build skips submodule mail processing without requiring toAddresses and sends one announcement for the whole project.

Written by the indexing model from the issue text.