Fix for GRADLE-3154

- The underlying issue seems to be setting properties during class initialization
  on a groovy class that is created via a decorating instantiator. Probably due
  to class decoration?
- The lightweight fix was to remove the parsing of a root application.xml file
  from inside the constructor of DefaultDeploymentDescriptor (this seems like a bad
  idea anyway). We now explicitly attempt to read from a root META-INF/application.xml.