gstlal-inspiral/python/stats/ fix missing missing file

- a file was added but not included in the packaging rules so it was
  missing from the tar ball.  this seems to fix

gstlal-inspiral/python/stats/Makefile.am

@@ -8,5 +8,5 @@ stats_PYTHON = \
 	inspiral_lr.py \
 	trigger_rate.py
 
-noinst_DATA = \
+EXTRA_DIST = \
 	__init__.py