inspiral_intrinsics.py: correct error formatting

gstlal-inspiral/python/stats/inspiral_intrinsics.py

@@ -135,7 +135,7 @@ class SourcePopulationModel(object):
 				try:
 					template_indices[template_id] = numpy.where(model_ids==template_id)[0][0]
 				except IndexError:
-					raise IndexError("template ID %d is not in this model".format(template_id))
+					raise IndexError("template ID %d is not in this model" % template_id)
 			self.polys = dict((template_id, PPoly(coefficients[:,:,[template_indices[template_id]]], snr_bp)) for template_id in template_ids)
 			self.max_snr = snr_bp.max()
 		else:
@@ -148,7 +148,7 @@ class SourcePopulationModel(object):
 		try:
 			lnP_vs_snr = self.polys[template_id]
 		except KeyError:
-			raise KeyError("template ID %d is not in this model".format(template_id))
+			raise KeyError("template ID %d is not in this model" % template_id)
 		# PPoly's .__call__() returns an array, so we need the
 		# final [0] to flatten it
 		return lnP_vs_snr(min(snr, self.max_snr))[0]