Fixes a problem where inheriting LoggingDisabled (like RequestFactory does) clobbers the value of gwt.logging.enabled for downstream modules.
Without this change RequestFactory apps were forced to set gwt.logging.enabled themselves, instead of just inheriting Logging.gwt.xml

Review at http://gwt-code-reviews.appspot.com/1451816

Review by: unnurg@google.com

git-svn-id: https://google-web-toolkit.googlecode.com/svn/trunk@10320 8db76d5a-ed1c-0410-87a9-c151d255dfc7