Fix a null-ref exception with no-proxy one-to-one
Fix a null-ref exception with no-proxy one-to-one

This null reference exception was swallowed and was only bloating
logs.

nhibernate/nhibernate-core,ngbrown/nhibernate-core,hazzik/nhibernate-core,ngbrown/nhibernate-core,ngbrown/nhibernate-core,RogerKratz/nhibernate-core,hazzik/nhibernate-core,gliljas/nhibernate-core,RogerKratz/nhibernate-core,fredericDelaporte/nhibernate-core,gliljas/nhibernate-core,RogerKratz/nhibernate-core,nhibernate/nhibernate-core,gliljas/nhibernate-core,hazzik/nhibernate-core,hazzik/nhibernate-core,nhibernate/nhibernate-core,gliljas/nhibernate-core,fredericDelaporte/nhibernate-core,nhibernate/nhibernate-core,fredericDelaporte/nhibernate-core,fredericDelaporte/nhibernate-core,RogerKratz/nhibernate-core