Janrhijn fix nullable properties not read #141

Job	Run time
Build .Net projects (samples/client/petstore/csharp/generichost/net4.7/FormModels)	1m 48s
Build .Net projects (samples/client/petstore/csharp/generichost/net4.7/AnyOfNoCompare)	2m 12s
Build .Net projects (samples/client/petstore/csharp/generichost/net4.7/AllOf)	1m 54s
Build .Net projects (samples/client/petstore/csharp/generichost/net4.7/AnyOf)	2m 16s
Build .Net projects (samples/client/petstore/csharp/generichost/net4.7/OneOf)	1m 22s
Build .Net projects (samples/client/petstore/csharp/generichost/net4.8/AnyOfNoCompare)	2m 8s
Build .Net projects (samples/client/petstore/csharp/generichost/net4.8/FormModels)	1m 27s
Build .Net projects (samples/client/petstore/csharp/generichost/net4.7/Petstore)	1m 28s
Build .Net projects (samples/client/petstore/csharp/generichost/net4.7/UseDateTimeForDate)	2m 11s
Build .Net projects (samples/client/petstore/csharp/generichost/net4.8/Petstore)	2m 1s
Build .Net projects (samples/client/petstore/csharp/generichost/net4.8/AnyOf)	2m 3s
Build .Net projects (samples/client/petstore/csharp/generichost/net4.8/UseDateTimeForDate)	1m 5s
Build .Net projects (samples/client/petstore/csharp/generichost/net4.8/OneOf)	2m 21s
Build .Net projects (samples/client/petstore/csharp/generichost/net4.8/AllOf)	1m 10s
	25m 26s

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