Merge pull request #360 from chr15m/issue-357-data-root

Add DATA_PATH to environment.

piku.py

@@ -725,6 +725,7 @@ def spawn_app(app, deltas={}):
     env = {
         'APP': app,
         'LOG_ROOT': LOG_ROOT,
+        'DATA_ROOT': join(DATA_ROOT, app),
         'HOME': environ['HOME'],
         'USER': environ['USER'],
         'PATH': ':'.join([join(virtualenv_path, 'bin'), environ['PATH']]),