Update NLogExtension.cs

Solves Issue 2 unitycontainer#2

src/NLogExtension.cs

@@ -25,7 +25,11 @@ public ResolveDelegate<BuilderContext> GetResolver(ref BuilderContext context)
             var method = GetName ?? _defaultGetName;
             Type declaringType = context.DeclaringType;
 
-            return (ref BuilderContext c) => LogManager.GetLogger(method(declaringType)); 
+            return (ref BuilderContext c) =>
+                {
+                    var declaringType = c.DeclaringType;
+                    return  LogManager.GetLogger(method(declaringType));
+                };
         }
     }
 }