Fix dump_dependency_json.
Fix dump_dependency_json.

dump_dependency_json needs to define CONFIGURATION_NAME like the other
generators, otherwise it fails when run on real projects.
Review URL: https://codereview.chromium.org/11271026
old8xp/gyp_from_google,old8xp/gyp_from_google,old8xp/gyp_from_google,old8xp/gyp_from_google,old8xp/gyp_from_google