Fix issue #7072 : can't create a feature when a layer has a join

[PhilippeDorelon]

It works fine with my data but not sure this is the best fix..

[wonder-sk]

Thanks for contributing the fix. (btw. something must have gone wrong and there are two lines of code on the last line in the diff)

I think the proper fix should actually chop the joined fields, because they are not really a part of the data - the joined fields should be appended automatically whenever someone iterates over layer's features.

[minorua]

works fine for me too. But replacing the conditional expression with the following is enough for the fix? Or is there much better fix?

if ( L->mUpdatedFields.count() != f.attributes().count() )

[PhilippeDorelon]

minuora yes your fix works fine and is much simpler than mine : tested with join, added fields and deleted fields.