Update reference_psd.py: fixing more test output

gstlal/python/reference_psd.py

@@ -272,13 +272,13 @@ class HorizonDistance(object):
 		>>> # compute distance and spectrum for SNR = 25
 		>>> D, (f, model) = horizon_distance(psd, 25.)
 		>>> "%.4g Mpc" % D
-		'139 Mpc'
+		'139.1 Mpc'
 		>>> f
 		array([   10.     ,    10.03125,    10.0625 , ...,  1023.9375 ,
 		        1023.96875,  1024.     ])
 		>>> model
-		array([  8.00942750e-45,   7.95221458e-45,   7.89520620e-45, ...,
-		         1.11473675e-49,   1.11465176e-49,   1.11456678e-49])
+		array([  8.05622865e-45,   7.99763234e-45,   7.93964216e-45, ...,
+		         1.11824864e-49,   1.11815656e-49,   1.11806450e-49])
 
 		NOTE: