tools: ratbagc - set the LIBRATBAG_DATA_DIR environment before context start

This way we use the data files from the source directory, not the installed
ones.

Fixes #530

Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>

tools/ratbagc.py.in

@@ -127,6 +127,7 @@ class Ratbagd(object):
     """
 
     def __init__(self):
+        os.environ['LIBRATBAG_DATA_DIR'] = LIBRATBAG_DATA_DIR
         self._ratbag = libratbag.ratbag_create_context(libratbag.interface, None)
         self._devices = {}
         self._devices_initialized = False