get gas damping temperature from suspension struct

gwinc/noise/residualgas.py

@@ -68,7 +68,12 @@ def residual_gas_damping(f, ifo, species, sustf, squeezed_film):
 
     :returns: displacement noise
     """
-    kT = ifo.Infrastructure.Temp * const.kB
+    sus = ifo.Suspension
+    if 'Temp' in sus.Stage[0]:
+        kT = sus.Stage[0].Temp * const.kB
+    else:
+        kT = sus.Temp * const.kB
+
     mass = species.mass
     radius = ifo.Materials.MassRadius
     thickness = ifo.Materials.MassThickness