Bank is empty if serializing fails

[Cu3PO42]

I came across this issue in conjunction with cfi2017/bl3-save-core#1. When attempting to store a character's item and the serialization fails, an error is generated and the operation aborted. However, if one tries to store an invalid item in the bank, no error will be reported. Instead the bank is completely empty.

I would expect the same behaviour as for characters: i.e. the operation to be aborted with an error.