Fixed updateConfiguations call when pruning prep network

Discussed in #58. @jwallen made the change in 4ef7e32,
just missed this case.

Author: pierrelb

rmgpy/rmg/model.py

@@ -1162,7 +1162,7 @@ def removeSpeciesFromEdge(self, spec):
                         network.netReactions.remove(rxn)
 
                     # Recompute the isomers, reactants, and products for this network
-                    network.updateConfigurations()
+                    network.updateConfigurations(self)
 
         # Remove from the global list of reactions
         # also remove it from the global list of reactions