FilteringGeneratorDelegate does not override writeStartObject(Object forValue)

[arnaudroger]

that leads to

Caused by: java.lang.NullPointerException
	at com.fasterxml.jackson.core.filter.FilteringGeneratorDelegate.writeFieldName(FilteringGeneratorDelegate.java:278)
	at com.fasterxml.jackson.databind.ser.BeanPropertyWriter.serializeAsField(BeanPropertyWriter.java:670)
	at com.fasterxml.jackson.databind.ser.std.BeanSerializerBase.serializeFields(BeanSerializerBase.java:690)
	... 43 more

when using the BeanSerializer

writeStartObject(Object forValue) should do the same as writeStartObject().

will submit a PR

[arnaudroger]

see #360

[cowtowncoder]

Merged for 2.8.8 / 2.9.0.pr2