Source release build needs to specify the 'Source' release info by default

The source release via the jira:sourcerelease maven goal builds a zip file with the JIRA source. We incorrectly added the releaseInfo=Source variable to the jira:sourcerelease goal, which actually has no effect whatsoever, since the release.info file only gets created when the war is built.

If a customer takes the source release zip and simply runs maven war:war the release.info file wont get created (the releaseInfo variable isn't set) and JIRA will show 'unknown' rather than 'Source'. We need to somehow default the release.info to 'Source' for the war:war build.